Faculty of Natural Sciences: Recent submissions

Now showing items 2441-2460 of 2527

    • Growth of market-size abalone (Haliotis midae) fed kelp (Ecklonia maxima) versus a low-protein commercial feed 

      Francis, Tamson; Maneveldt, Gavin; Venter, Jonathan (Taylor & Francis, 2008)
      The growth of grow-out abalone fed on kelp, with ca. 10 % dry weight protein content, was compared with that of those fed a new ,ca. 26 % protein, commercial feed in a flow-through system on a South African west coast ...

    • Effects of wild and farm-grown macroalgae on the growth of juvenile South African abalone Haliotis midae Linnaeus 

      Robertson-Andersson, Deborah; Maneveldt, Gavin; Naidoo, Krishni (Taylor and Francis, 2011)
      The effect of various macroalgal diets on the growth of grow-out (> 20 mm shell length) South African abalone Haliotis midae was investigated on a commercial abalone farm. The experiment consisted of four treatments: fresh ...

    • The effects of long-term exclusion of the limpet Cymbula oculus (Born) on the distribution of intertidal organisms on a rocky shore 

      Maneveldt, Gavin; Eager, Rosemary; Bassier, Aghmat (NISC (Pty) Ltd and Taylor & Francis, 2009)
      Zonation patterns on rocky shores are typically as a result of both physical factors and biological interactions. Physical factors generally set the upper limits of species distributions, while biological interactions ...

    • Determining the most appropriate feeding regime for the South African abalone Haliotis midae Linnaeus grown on kelp 

      Francis, Tamson; Maneveldt, Gavin; Venter, Jonathan (Springer Verlag, 2008)
      Beach-cast kelp (the most widely used feed for commercially grown South African abalone) is plentiful during winter months when periodic storms cause kelp to wash ashore. During summer, however, this resource is not ...

    • Internet protocol-based push to talk 

      Kobo, Hlabishi Isaac; Tucker, William David; Norman, Michael (Telkom, 2010)
      This paper discusses a way of offering voice instant messaging based on Internet Protocol using Session Initiation Protocol. The purpose of this investigation is to enhance the modern social communication amongst the people ...

    • Browser-based video communication for deaf people 

      Wang, Yuan Yuan; Tucker, William David (Telkom, 2009)
      This paper describes work in progress to to provide browser-based sign language communication for deaf users. The paper introduces the communication requirements for a disadvantaged Deaf community in Cape Town, describes ...

    • Telemedicine using VoIP combined with a store and forward approach 

      Chetty, Marshini; Tucker, William David; Blake, Edwin H. (Telkom, 2004)
      Rural areas in South Africa have unique conditions such as remoteness and scarcity of reliable public facilities. Information and Communication Technologies (ICTs) introduced into these areas must be suitable for these ...

    • Automatic voice relay with open source Kiara 

      Yi, Long; Tucker, William David (Telkom, 2009)
      One way for Deaf people to communicate with hearing people over the telephone is to use a voice relay. The service is often provided with a human relay operator that relays text into voice, and vice versa, on behalf of the ...

    • Call capacity for voice over Internet Protocol on wireless mesh networks 

      Zulu, Docas Dudu; Tucker, William David (Telkom, 2010)
      This paper describes work in progress on call capacity optimization for voice over Internet Protocol on wireless mesh networks. In a developing country such as South Africa, evidence has shown that rural inhabitants find ...

    • Bridging communications across the digital divide 

      Blake, Edwin H.; Tucker, William David (CTIT, 2004)
      Connecting people across the Digital Divide is as much a social effort as a technological one. We are developing a community-centered approach to learn how interaction techniques can compensate for poor communication across ...

    • Web-based telephony bridges for the deaf 

      Glaser, Meryl; Tucker, William David (Telkom, 2001)
      A Teldem provides text-based telephony services to the deaf. Despite an array of text-based communications mechanisms on the web, the Teldem is the only means of synchronous telecommunication available to a deaf person. ...

    • Telgo323: an H.323 Bridge for deaf telephony 

      Penton, Jason; Tucker, William David; Glaser, Meryl (Telkom, 2002)
      We have developed a prototype bridge that relays text and speech between Teldem, a text telephone for the Deaf, and a standard telephone or H.323 endpoint. Telgo323 uses modified H.323 media gateways and open source Text ...

    • SoftBridge: an architecture for building IP-based bridges over the digital divide 

      Lewis, John; Tucker, William David; Blake, Edwin H. (Telkom, 2002)
      Users and computing equipment have varying capabilities that include the abilities to exchange text and audio, engage in high bandwidth communication, etc. As the technological options increase, e ective communication ...

    • Socio-economic aspects of voice-over-IP technology in rural SA 

      Roro, Zukile; Rey-Moreno, Carlos; Tucker, William David; Siya, Masbulele Jay (Telkom, 2012)
      This paper describes work in progress towards developing a business case and preliminary design for an 802.11-based mesh network in the remote rural community of Mankosi in the Eastern Cape province of South Africa. Aside ...

    • Telecommunications bridging between deaf and hearing users in South Africa 

      Glaser, Meryl; Tucker, William David (2004)
      This paper presents a description of telecommunications for Deaf people in South Africa by contrasting the situation in the developed world. We explain the main motivations for providing a locally appropriate solution. ...

    • A Softbridge with carrier grade reliability using JAIN SLEE 

      Sun, Tao; Tucker, William David (Telkom, 2004)
      We have built a SoftBridge prototype within a JAIN (Java APIs for the Integrated Network) SLEE (Service Logic Execution Environment). A SoftBridge is a semi-synchronous multimodal IP (Internet Protocol) -based communication ...

    • Connecting bridges across the digital divide 

      Tucker, William David (ACM, 2004)
      Connecting people across the Digital Divide is as much a social effort as a technological one. We are developing a community-centered approach to learn how interaction techniques can compensate for poor communication across ...

    • Situation-aware routing for wireless mesh networks with mobile nodes 

      Kobo, Hlabishi Isaac; Tucker, William David (IIMC International Information Management Corporation, 2012)
      This paper describes a situation-aware algorithm based on the current situation of a mesh network with mobile nodes that improves quality of service. After running laboratory performance tests, we concluded that a ...

    • Use of coal fly ash as a catalyst in the production of biodiesel 

      Babajide, Omotola; Petrik, Leslie; Musyoka, Nicholas; Amigun, Bamikole; Ameer, Farouk (Slovnaft VÚRUP, 2010)
      South Africa is largely dependent on the combustion of coal for electricity production; Eskom’s coalfired power stations consume approximately 109 million tons of coal per annum, producing around 25 million tons of ash, ...

    • Low-Cost feedstock conversion to biodiesel via ultrasound technology 

      Babajide, Omotola; Leslie, Petrik; Amigun, Bamikole; Ameer, Farouk (MDPI, 2009)
      Biodiesel has attracted increasing interest and has proved to be a good substitute for fossil-based fuels due to its environmental advantages and availability from renewable resources such as refined and waste vegetable ...