Design and Fabrication of a Low Cost Traffic Manipulation Hardware Platform
- Authors: Pennefather, Sean , Irwin, Barry V W
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427873 , vital:72468 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622941_Design_and_Fabrication_of_a_Low_Cost_Traffic_Manipulation_Hardware/links/5b9a1625458515310583fc8c/Design-and-Fabrication-of-a-Low-Cost-Traffic-Manipulation-Hardware.pdf
- Description: This paper describes the design and fabrication of a dedicated hardware platform for network traffic logging and modification at a production cost of under $300. The context of the device is briefly discussed before characteristics relating to hardware development are explored. The paper concludes with three application examples to show some to the potential functionality of the platform. Testing of the device shows an average TCP throughput of 84.44 MiB/s when using the designed Ethernet modules.
- Full Text:
- Date Issued: 2015
Facile synthesis and biological evaluation of assorted indolyl-3-amides and esters from a single, stable carbonyl nitrile intermediate
- Authors: Veale, Clinton G L , Edkins, Adrienne L , de la Mare, Jo-Anne , de Kock, Carmen , Smith, Peter J , Khanye, Setshaba D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66221 , vital:28919 , https://doi.org/10.1016/j.tetlet.2015.02.090
- Description: publisher version , The synthesis of biologically relevant amides and esters is routinely conducted under complex reaction conditions or requires the use of additional catalysts in order to generate sensitive electrophilic species for attack by a nucleophile. Here we present the synthesis of different indolic esters and amides from indolyl-3-carbonyl nitrile, without the requirement of anhydrous reaction conditions or catalysts. Additionally, we screened these compounds for potential in vitro antimalarial and anticancer activity, revealing 1H-indolyl-3-carboxylic acid 3-(indolyl-3-carboxamide)aminobenzyl ester to have moderate activity against both lines.
- Full Text: false
- Date Issued: 2015
FPGA Based Implementation of a High Performance Scalable NetFlow Filter
- Authors: Herbert, Alan , Irwin, Barry V W , Otten, D F , Balmahoon, M R
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427887 , vital:72470 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622948_FPGA_Based_Implementation_of_a_High_Perfor-mance_Scalable_NetFlow_Filter/links/5b9a17a192851c4ba8181ba5/FPGA-Based-Implementation-of-a-High-Performance-Scalable-NetFlow-Filter.pdf
- Description: Full packet analysis on firewalls and intrusion detection, although effec-tive, has been found in recent times to be detrimental to the overall per-formance of networks that receive large volumes of throughput. For this reason partial packet analysis algorithms such as the NetFlow protocol have emerged to better mitigate these bottlenecks. This research delves into implementing a hardware accelerated, scalable, high per-formance system for NetFlow analysis and attack mitigation. Further-more, this implementation takes on attack mitigation through collection and processing of network flows produced at the source, rather than at the site of incident. This research platform manages to scale out its back-end through dis-tributed analysis over multiple hosts using the ZeroMQ toolset. Fur-thermore, ZeroMQ allows for multiple NetFlow data publishers, so that plug-ins can subscribe to the publishers that contain the relevant data to further increase the overall performance of the system. The dedicat-ed custom hardware optimizes the received network flows through cleaning, summarization and re-ordering into an easy to pass form when given to the sequential component of the system; this being the back-end.
- Full Text:
- Date Issued: 2015
How general-purpose can a GPU be?
- Authors: Machanick, Philip
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61180 , vital:27988 , http://dx.doi.org/10.18489/sacj.v0i57.347
- Description: The use of graphics processing units (GPUs) in general-purpose computation (GPGPU) is a growing field. GPU instruction sets, while implementing a graphics pipeline, draw from a range of single instruction multiple datastream (SIMD) architectures characteristic of the heyday of supercomputers. Yet only one of these SIMD instruction sets has been of application on a wide enough range of problems to survive the era when the full range of supercomputer design variants was being explored: vector instructions. Supercomputers covered a range of exotic designs such as hypercubes and the Connection Machine (Fox, 1989). The latter is likely the source of the snide comment by Cray: it had thousands of relatively low-speed CPUs (Tucker & Robertson, 1988). Since Cray won, why are we not basing our ideas on his designs (Cray Inc., 2004), rather than those of the losers? The Top 500 supercomputer list is dominated by general-purpose CPUs, and nothing like the Connection Machine that headed the list in 1993 still exists.
- Full Text:
- Date Issued: 2015
How General-Purpose can a GPU be?
- Authors: Machanick, Philip
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439294 , vital:73563 , https://hdl.handle.net/10520/EJC181693
- Description: The use of graphics processing units (GPUs) in general-purpose computation (GPGPU) is a growing field. GPU instruction sets, while implementing a graphics pipeline, draw from a range of single instruction multiple data stream (SIMD) architectures characteristic of the heyday of supercomputers. Yet only one of these SIMD instruction sets has been of application on a wide enough range of problems to survive the era when the full range of supercomputer design variants was being explored: vector instructions.
- Full Text:
- Date Issued: 2015
Human myiasis in rural South Africa is under-reported
- Authors: Kuria, Simon K , Villet, Martin H , Kingu, H J C , Dhaffala, Adupa
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442425 , vital:73983 , https://www.ajol.info/index.php/samj/article/view/114028
- Description: Background. Myiasis is the infestation of live tissue of humans and other vertebrates by larvae of flies. Worldwide, myiasis of humans is seldom reported, although the trend is gradually changing in some countries. Reports of human myiasis in Africa are few. Several cases of myiasis were recently seen at the Mthatha Hospital Complex, Mthatha, Eastern Cape Province, South Africa (SA).
- Full Text:
- Date Issued: 2015
Influence of mouth status on population structure of southern African endemic estuarine-spawning ichthyofauna in a temperate, temporarily open/closed estuary
- Authors: Tweddle, Gavin P , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68071 , vital:29195 , https://doi.org/10.2989/16085914.2015.1051940
- Description: Publisher version , The effect of mouth status on the population structure of three endemic estuarine-spawning fish species was assessed using seine nets from November 2005 to October 2007 in the temporarily open/closed Mpekweni Estuary, Eastern Cape, South Africa. Collectively, these three species accounted for more than 60% of the total fish abundance within the estuary. Monthly length frequency data were analysed. Two species, Gilchristella aestuaria and Glossogobius callidus, displayed normally distributed populations throughout, with recruitment/abundance peaks between spring and autumn, and were unaffected by open mouth and extended marine connection conditions. Atherina breviceps, however, displayed multiple modal peaks in its combined population distribution, suggesting a greater influence of mouth condition on its population structure. Retrospective analyses of the various cohorts for A. breviceps identified peaks in recruitment/abundance during summer, coinciding with open-mouth conditions and, to a lesser extent, with overwash events. This study highlights the importance of mouth phase, not only on the recruitment and population distribution of marine-spawning species, but also on estuarine-spawning fish in temporarily open/closed estuaries along the South African coastline.
- Full Text: false
- Date Issued: 2015
Making media theory from the South:
- Authors: Garman, Anthea
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158873 , vital:40236 , https://doi.org/10.1080/23743670.2015.1008186
- Description: Like many other academics who have joined the digital age I have pages and uploads on Academia.edu, Researchgate, LinkedIn and a Google Scholar-aggregated thing (that seemed to trawl the net for my papers, do it for me and then invite me to view my own collection!). So, I get lots of email alerts telling me when someone has looked at my work and downloaded my papers. I appreciate this virtual community and enjoy participating in it, but the aspect of this that perplexes me is the need to ‘endorse’’ someone for their skills – a practice that seems to stem from LinkedIn’s businessmindedness aimed at youngsters trying to find a foothold on the career ladder. I don’t do endorsements unless the programme forces me to go through this step in order to do what I want to do on the site.
- Full Text:
- Date Issued: 2015
Shifting the priority from giving voice to listening: journalism new
- Authors: Garman, Anthea , Malila, Vanessa
- Date: 2015
- Language: English
- Type: text , article
- Identifier: vital:38355 , http://hdl.handle.net/10520/EJC175773
- Description: If, as the critics have argued, the South African media prioritise the voices of elite, middleclass South Africans, then the majority of South Africans are certainly invisible in the mainstream media. Kate Lacey argues that "listening is at the heart of what it means to be in the world, to be active, to be political" (2013: 163), and as such more than just providing a 'voice' for citizens, the media needs to be engaged in active listening to allow audiences to feel 'heard'. Servaes and Malikhao argue that people are 'voiceless' not because they have nothing to say, but because "nobody cares to listen to them" (2005: 91).
- Full Text:
- Date Issued: 2015
Subjective well-being in Africa
- Authors: Botha, Ferdi , Snowball, Jeanette D
- Date: 2015
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61084 , vital:27946
- Description: Research on quality of life and subjective well-being (SWB) has witnessed a remarkable growth over the past four decades or so. Since Easterlin’s (1974) seminal contribution on the relationship between happiness and income, thousands of studies have followed that examine the intricacies of subjective well-being (for reviews, see Frey and Stutzer, 2002; Dolan et al., 2008; MacKerron, 2012). These studies have uncovered some very important aspects of individual well-being and have pointed to the fact that money or income is not always (as is often assumed) the most important determinant of SWB.
- Full Text:
- Date Issued: 2015
The effects of tissue type and body size on δ13C and δ15N values in parrotfish (Labridae) from Zanzibar, Tanzania
- Authors: Plass-Johnson, Jeremiah G , McQuaid, Christopher D , Hill, Jaclyn M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444638 , vital:74256 , https://doi.org/10.1111/jai.12746
- Description: Differences between the stable isotopic ratios (δ13C and δ15N) of two tissues (blood and muscle) from four species of East African coral reef parrotfishes (family: Labridae, tribe: Scarini) were analysed across a broad spectrum of body sizes. Comparison of isotopic ratios between the tissues allowed the assessment of using blood as an alternative tissue to muscle. In 2010–2011, constant differences between tissues (δblood minus δmuscle) were found across a broad range of sampled fish lengths. Linear relationships between the tissues, specific for an isotope, indicate that constants could be generated for converting blood isotope into muscle isotope values. Only one species, Chlorurus sordidus, displayed an inconsistent difference between tissues in δ15N, indicating that this ratio was dependent on fish length. The δ13C of both tissues was positively related linearly to fish length for three species, while δ15N showed no relationship with body length. The results are interpreted as indicating dietary consistency over days to weeks, the time of tissue turnover for blood and muscle, respectively. Lastly, differences among the species, even closely related species, show that the generation of tissue conversion constants is species‐specific.
- Full Text:
- Date Issued: 2015
The law of divorce and dissolution of life partnerships in South Africa: book review
- Authors: Kruuse, Helen
- Date: 2015
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54129 , vital:26394 , http://scholar.ufs.ac.za:8080/xmlui/handle/11660/2454
- Description: Jackie Heaton’s latest contribution to the family law domain is formidable – 777 pages of carefully crafted opinions and discussions of the law affecting divorce and dissolution of life partnerships. Given the range, diversity and depth of issues in this area, it is no wonder that she calls on those being among the best in their field to assist her in writing up the book.
- Full Text:
- Date Issued: 2015
A critical analysis of Umfi uJonathan Tunyiswa noWilliam Cebani Mtoba as one of the unpublished biographical poems by SEK Mqhayi
- Authors: Mazwi, Ntosh R-M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/467968 , vital:76995 , https://doi.org/10.1080/02572117.2014.896524
- Description: This study analysed the literary qualities of a specific biographical poem of Mqhayi with particular reference to his artistry in promoting sentiments like loyalty, love, pride and attachment to one's country (patriotism). The poem under scrutiny was transcribed, translated and analysed using literary analysis. One of the reasons for undertaking this research was to endorse in some practical way the view articulated by Qangule (1979:259) that throughout his publications Mqhayi made references or allusions to the following: Holy scriptures, prominent leaders and historical incidents in South Africa and abroad and African and European culture and lore. It means, Mqhayi's poems were written in tribute to different people of different stature, in life or after death. To achieve the aims and objectives of this study a qualitative research methodology was used in order to understand meanings, look at, describe and understand experience, ideas, beliefs and values (Wisker, 2001:138). The method was therefore descriptive, investigative, interpretative and analytical, with the specific aim of showing how Mqhayi had artistically used the literary devices in his praise poem. The main focus was on the literary qualities exemplified in the poem to reveal how Mqhayi paid tribute to a South African hero, Jonathan Tunyiswa, who had contributed to the development of our country.
- Full Text:
- Date Issued: 2014
An exploration of geolocation and traffic visualisation using network flows
- Authors: Pennefather, Sean , Irwin, Barry V W
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429597 , vital:72625 , 10.1109/ISSA.2014.6950
- Description: A network flow is a data record that represents characteristics associated with a unidirectional stream of packets transmitted between two hosts using an IP layer protocol. As a network flow only represents statistics relating to the data transferred in the stream, the effectiveness of utilizing network flows for traffic visualization to aid in cyber defense is not immediately apparent and needs further exploration. The goal of this research is to explore the use of network flows for data visualization and geolocation.
- Full Text:
- Date Issued: 2014
Design of a Network Packet Processing platform
- Authors: Pennefather, Sean , Irwin, Barry V W
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427901 , vital:72472 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622772_Design_of_a_Network_Packet_Processing_platform/links/5b9a187f92851c4ba8181bd6/Design-of-a-Network-Packet-Processing-platform.pdf
- Description: This paper describes the design considerations investigated in the implementation of a prototype embedded network packet processing platform. The purpose of this system is to provide a means for researchers to process, and manipulate network traffic using an embedded standalone hardware platform, with the provision this be soft-configurable and flexible in its functionality. The performance of the Ethernet layer subsystem implemented using XMOS MCU’s is investigated. Future applications of this prototype are discussed.
- Full Text:
- Date Issued: 2014
Editors reflect on the state of journalism: the cha(lle)nging media space
- Authors: Malila, Vanessa
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158650 , vital:40218 , https://hdl.handle.net/10520/EJC159502
- Description: Trying to understand how journalists and editors in the South African media landscape think about the work they do and the environment in which they work is not easy. However, while many of us speculate about why things are reported on in one way or another, this article gets to the heart of the issue - or the mouth - by speaking to journalists and editors about the work they do and how things have changed in the last few years within this complex institution we call the media.
- Full Text:
- Date Issued: 2014
Natural resource products contribute to poverty mitigation amongst urbanising communities in sub-saharan Africa
- Authors: Shackleton, Charlie M , Schlesinger, Johannes , Kaoma, Humphrey , Davenport, N I , Ward, Catherine D , Evans, Michelle L , Drescher, Axel W
- Date: 2014
- Language: English
- Type: text
- Identifier: vital:6624 , http://hdl.handle.net/10962/d1016232
- Description: [From Introduction] Urbanisation in sub-Saharan Africa: changing the locus of poverty. Urbanisation is a global phenomenon that is changing the face of the Earth, as well as how people earn a living and secure their livelihoods. In 2006 the number of urban people in the world surpassed the number of rural people, and this gap will continue to grow. In only 16 years (by 2030) just under two-thirds of the world's people will be urban dwellers. Whilst most of the developed world and large parts of Latin America already have more than threequarters of their populations living in cities and towns, most countries in Asia and sub-Saharan Africa are still catching up. This means that they are experiencing massive migrations from rural to urban areas as rural people wish to swap the insecurities of rural living for the allure of secure employment and better services for health, education, sanitation and transport in towns and cities. Sub-Saharan Africa (SSA) is the most rapidly urbanising region of the globe. According to UN-Habitat, in 1990, only 28 % of the region's inhabitants lived in towns and cities; that increased to approximately 32 % in 2001 and 41 % in 2010. The size of the urban population is likely to surpass the rural one around 2025. Contrary to popular belief, most urban residents in SSA (and globally) live in small towns rather than massive megacities; with just over half living in towns of less than 200,000 people and 78 % living in towns of less than 500,000 residents. Only 14 % of urban dwellers live in cities of more than one million people. Many new urban households maintain strong links to relatives and clans in rural areas, with circular migration patterns emerging as the urban transition takes place over several decades. The implications of this extremely rapid urbanisation in SSA countries for livelihoods and poverty are widely debated. UN-Habitat highlights a relatively unique aspect of urbanisation in SSA as being the accompanying high rate of growth in informal settlements or slums. In other words, not all rural migrants to towns and cities find secure incomes or shelter. Some slum areas have become permanent features where inter-generational poverty is reproduced. Although urban areas are producing an increasing share of national wealth in SSA countries, some argue that slowly the nexus of poverty is shifting towards urban areas. Rates of poverty are high in rural areas of SSA, but migration and internal population growth means that in some countries the number of urban poor almost matches the number of rural poor, and it is likely to grow. The informal economy contributes an average of 40 – 45 % of total urban GDP, which is higher than any other region of the world.
- Full Text:
- Date Issued: 2014
New possibilities for research on reef fish across the continental shelf of South Africa
- Authors: Bernard, Anthony T F , Götz, Albrecht , Parker, Daniel M , Heyns, Elodie R , Halse, Sarah J , Riddin, N A , Smith, M K S , Paterson, Angus W , Winker, A Henning , Fullwood, L , Langlois, T J , Harvey, E S
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6971 , http://hdl.handle.net/10962/d1014566
- Description: [From introduction] Subtidal research presents numerous challenges that restrict the ability to answer fundamental ecological questions related to reef systems. These challenges are closely associated with traditional monitoring methods and include depth restrictions (e.g. safe diving depths for underwater visual census), habitat destruction (e.g. trawling), mortality of target species (e.g. controlled angling and fish traps), and high operating costs (e.g. remotely operated vehicles and large research vessels. Whereas many of these challenges do not apply or are avoidable in the shallow subtidal environment, the difficulties grow as one attempts to sample deeper benthic habitats. This situation has resulted in a paucity of knowledge on the structure and ecology of deep water reef habitats around the coast of South Africa and in most marine areas around the world. Furthermore, the inability to effectively survey deep water benthic environments has limited the capacity of researchers to investigate connectivity between shallow and deep water habitats in a standardised and comparable fashion.
- Full Text:
- Date Issued: 2014
Ocean warming hotspots provide early warning laboratories for climate change impacts
- Authors: Pecl, Gretta T , Hobday, Alistair J , Frusher, Stewart , Sauer, Warwick H H , Bates, Amanda E
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125363 , vital:35776 , https://doi.10.1007/s11160-014-9355-9
- Description: A growing literature describes a wide range of negative impacts of climate change on marine resources and the people and communities they support, including species range changes, changes in productivity of fisheries and declines in economic performance (Doney et al. 2012; Poloczanska et al. 2013). These impacts, many of which are projected to increase in future, are compounded by growing pressures on marine resources (Halpern et al. 2008; Maxwell et al. 2013). An estimated 260 million people are involved directly or indirectly in global marine fisheries (Teh and Sumaila 2013) with many of the resources for capture fisheries already fully (&57 % in 2009) or over exploited (30 %) (FAO 2012). Nevertheless, production of marine resources will need to increase to accommodate the demands of a growing population, and the impacts of climate change on food security will need to be minimised (FAO 2009). Identifying opportunities and threats, and developing adaptation options in response to climate change impacts in the marine realm, is essential for optimising the benefits that society can continue to derive from the goods and services provided by marine resources.
- Full Text:
- Date Issued: 2014
Primary wing-moult and site fidelity in South African mousebirds (Coliidae)
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hulley, Patrick E , Underhill, George D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449474 , vital:74824 , https://doi.org/10.2989/00306525.2014.931310
- Description: Based on large samples of birds mist-netted in the Eastern Cape and the Western Cape, moult of the primary remiges in both Speckled Mousebirds Colius striatus and Red-faced Mousebirds Urocolius indicus occurred throughout the year with no regional or seasonal patterns evident. The same picture emerged for the White-backed Mousebird Colius colius in the Western Cape. This aseasonality of wing-moult for all three species in South Africa was further supported by the full data set of moult records available in the Safring database. We were thus unable to use the Underhill–Zucchini model to estimate the moult parameters for these species, but an extended moult period seems likely. Recapture data for the Eastern Cape strongly suggest that Speckled Mousebirds are resident or revisit sites frequently, whereas this is not the case for Red-faced Mousebirds.
- Full Text:
- Date Issued: 2014