Thesis (MNutr (Interdisciplinary Health Sciences. Human Nutrition))--University of Stellenbosch, 2009. / Background: In Africa, internet access and use is plagued by numerous barriers. Whilst South Africa (SA) boasts a better population penetration than the rest of Africa there is a lack of regulation regarding the internet and e-mail use amongst health professionals and their patients. The aim of this study was to assess the use of the internet amongst dietitians and medical doctors (MDs) in clinical practice in SA and draft a policy on such usage amongst health professionals and their patients. Methods: A cross-sectional analytical web-based survey was conducted amongst registered dietitians and MDs. A cover letter including a hyperlink to the self-administered questionnaire was e-mailed to all dietitians and a proportionate, stratified random sample of MDs with contactable e-mail addresses. The questionnaire consisted of open and closed questions, including demographics, influence of the internet on the quality of care of patients, quality control with web resources and aspects of information technology (IT) which were recommended by health professionals to be incorporated as part of undergraduate health science education Results: A total of 176 health professionals participated in the study (106 dietitians and 70 MDs). The mean age of the dietitians was 32.6± (8.0) and the MDs 50.5± (8.9). The majority of the respondents in this study population were White (82%) females (67%). On average, practitioners had been in practice for 9.1(8.0) years. The majority of dietitians (58%) and MDs (68%) had access to the internet at both their practice or workplace and their home. More dietitians (65%) than MDs (41%) were using e-mail or internet. MDs did not use the internet for research purposes, whilst a fifth of dietitians (21%) reported using the internet as a research tool. A greater percentage of the sample [MDs (69%) and dietitians (82%)] reported that, the internet had improved the quality of care of their patients. The dietitians (60%) and MDs (53%) in this study sample were unclear about how to source information and determine the reliability or accuracy of the information obtained from internet resources. Conclusion: Internet is incorporated into the practice of most dietitians and to a lesser extent by MDs. In this study, the need for training amongst health professionals regarding the use of the internet was highlighted. The study reflects that even though health professionals were unsure of the credibility of the internet information resourced, it did not stop the use of the internet in the practice. This is an area of concern, since it could potentially result in the distribution of misinformation. This warrants regulation on the use of the internet in health practices in SA. A policy on the use of IT in health care practice has been drafted. Further research on the use of IT in the healthcare practice is required before the policy can be finalized. The advantage is that some elementary information is now available. The challenge is to ensure that the time lapse between additional research, policy finalization and policy implementation is kept to a minimum. / OPSOMMING: Agtergrond: In Afrika is internet toegang en gebruik met baie hindernisse belas. Alhoewel Suid-Afrika (SA) met ‘n beter bevolkingspenetrasie as die res van Afrika spog is daar ‘n gebrek aan regulasie in verband met internet en e-pos gebruik tussen gesondheidswerkers en hul pasiënte. Die doel van hierdie studie was om die gebruik van die internet deur dieetkundiges en mediese dokters (MDs) in kliniese praktyk in SA te assesseer en om ‘n konsepbeleid rakende sulke gebruik tussen gesondheidswerkers en hul pasiënte op te stel. Metode: ‘n Dwarssnit analitiese web-gebaseerde opname is met geregisteerde dieetkundiges en MDs onderneem. ‘n Dekkingsbrief met ‘n webskakeling (hyperlink) tot die selfgeadministreerde vraelys is aan alle dieetkundiges en aan ‘n eweredig, gestratifiseerde ewekansige steekproef van MDs met kontakbare e-pos adresse gestuur. Die vraelys het uit oop en toe vrae bestaan, insluitend demografie, invloed van die internet op die kwaliteit van sorg van pasiënte, kwaliteitskontrole met web-hulpmiddels en aspekte van informasie tegnologie (IT) wat deur gesondheidswerkers aanbeveel was om deel te word van voorgraadse gesondheidswetenkaplike onderrig. Resultate: ‘n Totaal van 176 gesondheidswerkers het aan die studie deelgeneem (106 dieetkundiges en 70 MDs). Die gemiddelde ouderdom van die dieetkundiges was 32.6± (8.0) jaar en die MDs 50.5± (8.9) jaar. Die meerderheid respondente in hierdie studie populasie was blank (82%) en vroulik (67%). Oor die algemeen was praktisyne vir 9.1± (8.0) jaar in praktyk. Die meerderheid dieetkundiges (58%) en MDs (68%) het toegang tot die internet by beide hul praktyk of werkplek en hul huis. Meer dieetkundiges (65%) as MDs (41%) het e-pos of internet gebruik. MDs het nie die internet vir navorsingsdoeleindes gebruik nie, terwyl ‘n vyfde van dieetkundiges (21%) raporteer het dat hulle die internet vir navorsingsdoeleindes gebruik het. ‘n Groot persentasie van die populasie [MDs (69%) en dieetkundiges (82%)] het gerapporteer dat die internet tot ‘n verbetering in sorg van hul pasiënte gelei het. Die dieetkundiges (60%) en MDs (53%) in hierdie studie was onseker hoe om informasie te verkry en die betroubaarheid en akuraatheid van die informasie vanaf internetbronne te bevestig. Opsomming: In hierdie studie word internet in die praktyke van die meerderheid dieetkundiges en tot ‘n mindere mate in die van MDs geinkorporeer. Die noodsaaklikheid vir opleiding in die gesondheidsberoepe met betrekking tot die gebruik van die internet is aan die lug gebring. Hierdie studie weerspieël dat alhoewel gesondheidswerkers onbewus was van die geloofwaardigheid van internet informasie, dit nie die gebruik van die internet in hul praktyk gestop het nie. Dit is ‘n area van kommer aangesien dit potensieel na die verspreiding van misinformasie kan lei. Dit motiveer dus reguleering van die gebruik van die internet in gesondheidspraktyke in SA. ‘n Beleid oor die gebruik van IT in gesondheidspraktyke is in konsepvorm opgetrek. Verdere navorsing oor die gebuik van IT in gesondheidspraktyke word benodig om die konsepbeleid te finaliseer. Die voordeel is dat basiese inligting nou beskikbaar is. Die uitdaging is om te verseker dat die tydsduur tussen addisionele navorsing, beleidsfinaliseering en beleidsimplementering tot ‘n minimum gehou word.

Thesis (MSc (Mathematical Sciences. Computer Science))--University of Stellenbosch, 2007. / It is widely recognized that Traffic engineering (TE) mechanisms have to be added to the IP transport functionalities to provide QoS guarantees while ensuring efficient use of network resources. Traffic engineering is a network management technique which routes traffic to where bandwidth is available in the network to achieve QoS agreements between current and future demands and the available network resources. Multi-path routing has been proven to be a more efficient TE mechanism than Shortest Path First (SPF) routing in terms of proffit maximization and resource usage optimization. However the identiffication of set of paths over which traffic is forwarded from source to the destination and the distribution of traffic among these paths are two issues that have been widely addressed by the IP community but remain an open issue for the emerging generation IP networks. Building upon different frameworks, this thesis revisits the issue of multi-path routing to present and evaluate the performance of different traffic splitting mechanisms to achieve QoS routing in Multi-Protocol Label Switching (MPLS) and Wireless Sensor Networks (WSNs). Three main contributions are identified in this thesis. First, we extend an optimization model that used the M/M/1 queueing model on a simple network consisting of a single source-destination pair by using the M/M/s queueing model on a general network consisting of several source-destination pairs. The model solves a multi-path routing problem by defining a Hamiltonian as a function of delay incurred and subjecting this Hamiltonian to Pontryagin's cost minimization to achieve efficient diffusion of traffic over the available parallel paths. Second, we revisit the problem of cost-based optimization in a multi-path setting by using a Game theoretical framework to propose and evaluate the performance of competitive and cooperative multi-path routing schemes and the impact of the routing metric (cost) on the difference between these two schemes. Finally, building upon a previously proposed optimization benchmark, we propose an Energy constrained QoS routing scheme for Wireless Sensor Networks and show through simulation that our scheme outperforms the benchmark scheme.

Thesis (MPhil)--University of Stennbosch, 2001.Thesis / ENGLISH ABSTRACT: The Internet connects millions of computers and people from all over the world with each other. A few clicks with a mouse are usually enough to gain access to the computers of almost any university in the world. But it is not only professors and researchers with years of experience who publish on the Internet. Anyone can publish anything for any reason without any editing or verification of the content. The Web is a valuable source of the information needed by science journalists to confirm facts of stories or to gain background information on a subject - if they know that the information is reliable. This web site identifies and discusses criteria to help establish the credibility of a web site. The Internet consists of far more than just the World Wide Web. The World Wide Web is, however, the most talked-about and bestknown part of the Internet, and the criteria discussed on this web site are applicable to the World Wide Web alone. With a little common sense and the necessary adaptations they can, however, be used to determine the credibility of information found on other parts of the Internet. Science journalists, students using the Web for research, and any other Web surfer will benefit from reading this document. Anybody can publish on the Web. Is there a set of rules that can be applied to a web site to measure its credibility? What are these rules? o FjrsUI1~ssion1i Is the layout professional? Is the site user friendly? Is the style appropriate for the type of information? Is the document free of spelling mistakes and grammatical errors? Does it take too long to load? o The_Contel1!Are there flaws in the logic used? Is the writer biased? Is there any verification for this information? Is the information accurate and complete? o A~ When was the web page published? Are there many broken links? o Sourc(?.<,)f theJnt'oxmation Who is the author? Who is the publisher? What do others have to say about this web site? o P1!!]2_O~e/Targ~_lAudiel1W~~ho is the target audience? What does the user want from the web site? What is the purpose of the web site? Who gains what? A summary of the criteria in tabular form is available here. The criteria discussed on this web site are only guidelines. Some criteria are more important than others. The situation will determine the relevance of each of the criteria. The origin of the information, the purpose thereof and the logic used are usually the most important criteria. The most important rule, however, is the use of common sense. Examine more than one source and compare them with one another. An intelligent decision regarding the credibility of the information can only be made when all (or most) sides ofa matter have been examined. / AFRIKAANSE OPSOMMING: Die Internet verbind miljoene rekenaars en mense regoor die aarde met mekaar. Net 'n paar klieke van 'n muis kan toegang verskaftot die rekenaars van amper enige universiteit in die wêreld. Dit is egter nie net professors en navorsers met jare se ervaring in hul veld wat hul bevindinge op die Wêreldwye Web publiseer nie. Enige-iemand kan enige-iets om enige rede publiseer sonder dat dit deur enige-iemand gelees of goedgekeur hoef te word. Die Web is 'n waardevolle bron van die tipe inligting wat wetenskap-joernaliste nodig het om die feite van hul stories te bevestig, of om agtergrondinligting oor 'n onderwerp in te samel - mits hulle seker is dat die inligting vertrou kan word. Hierdie webwerf identifiseer en bespreek verskillende kriteria wat kan help om die gehalte van die inhoud van 'n webwerfte bepaal. Die Wêreldwye Web is die bekendste deel van die Internet. Die riglyne is van toepassing op die Web alleen, maar kan met aanpassings ook op die ander dele van die Web gebruik word. Wetenskapjoernaliste, studente wat die Web gebruik vir navorsing, en enige webgebruiker sal baat vind by hierdie webwerf. Te veel mense kan publiseer. Is daar 'n stel reëls waarvolgens 'n webwerf gemeet kan word wat sal verseker dat die inhoud akkuraat en betroubaar is? Wat is daardie reëls? By die ondersoek na die gehalte van die inhoud van 'n webwerf, kan die volgende in gedagte gehou word: o Eerst_ell1ilnlkke Is die uitleg professioneel? Is die werf gebruikersvriendelik? Pas die skryfstyl by die tipe inligting? Is die dokument vol spel- en taalfoute? Laai die dokument vinnig af? o (_J~loof\yaarciigl1Yidyangi_eJnhQlIC!Is die logika wat gebruik word, logies? Is die skrywer objektief? Is daar enige ondersteuning vir hierdie inligting? Is die inligting akkuraat en volledig? o Ouci~Jd9n}Wanneer is die webbladsy gepubliseer? Is dit vol gebreekte skakels? o Qie o_QGiPJ:Qllg_Ygji1e1i1llligting Wie is die skrywer? Wie is die uitgewer of instansie? Wat het ander oor die webwerf te sê? o Q()elL(_J~h()()I Wie is die teikengehoor? Wat is die gebruiker se doel daarmee? Wat is die webwerf se doel? Waar lê die geld? 'n Opsomming van die kriteria in tabelvorm is hLer beskikbaar Die kriteria wat op hierdie webwerf bespreek word, is slegs riglyne. Sommige kriteria is belangriker as ander. Waardie inligting vandaan kom, wie verantwoordelik is daarvoor en wat die doel is daarmee is dalk die belangrikste vrae. Die belangrikheid van die ouderdom van die inligting hang van die tipe inligting wat ondersoek word, af. Die belangrikste reël by die beoordeling van 'n webwerf blyegter gesonde verstand. Meer as een bron moet ondersoek en met mekaar vergelyk word. Eers as alle (of genoeg) kante van 'n saak ondersoek word, kan 'n ingeligte besluit oor die akkuraatheid van inligting geneem word.

Wikipedia is no longer just another source of knowledge about the world. It is fast becoming a central source, used by other powerful knowledge brokers like Google and Bing to offer authoritative answers to search queries about people, places and things and as information infrastructure for a growing number of Web applications and services. Researchers have found that Wikipedia offers a skewed representation of the world that favours some groups at the expense of others so that representations on the platform have repercussions for the subjects of those representations beyond Wikipedia's domain. It becomes critical in this context to understand how exactly Wikipedia's representations come about, what practices give rise to them and what socio-technical arrangements lead to their expression. This ethnographic study of Wikipedia explores the values, principles and practices that guide what knowledge Wikipedia represents. It follows the foundational principles of Wikipedia in its identity both as an encyclopaedia and a product of the free and open source software and internet freedom rhetoric of the early 2000s. Two case studies are analysed against the backdrop of this ideology, illustrating how different sets of actors battle to extend or reject the boundaries of Wikipedia, and in doing so, affect who are defined as the experts, subjects and revolutionaries of the knowledge that is taken up. The findings of this thesis indicate that Wikipedia's process of decision-making is neither hierarchical nor is it egalitarian; rather, the power to represent on Wikipedia is rhizoid: it happens at the edges rather than in the centre of the network. Instead of everyone having the same power to represent their views on Wikipedia, those who understand how to perform and speak according to Wikipedia's complex technical, symbolic and policy vocabulary tend to prevail over those who possess disciplinary knowledge about the subject being represented. Wikipedians are no amateurs as many would have us believe; nor are they passive collectors of knowledge held in sources; Wikipedians are, instead, active co-creators of knowledge in the form of facts that they support using specially chosen sources. The authority of Wikipedia and Wikipedians is garnered through the performative acts of citation, through the ability of individual editors to construct the traces that represent citation, and through the stabilization and destabilization of facts according to the ideological viewpoints of its editors. In venerating and selecting certain sources among others, Wikipedians also serve to reaffirm traditional centres of authority, while at the same time amplifying new centres of knowledge and denying the authority of knowledge that is not codified in practice. As a result, Wikipedia is becoming the site of new centres of expertise and authoritative knowledge creation, and is signalling a move towards the professionalization of the expertise required to produce factual data in the context of digital networks.

Monitoring unused IP address space by using network telescopes provides a favourable environment for researchers to study and detect malware, worms, denial of service and scanning activities. Research in the field of network telescopes has progressed over the past decade resulting in the development of an increased number of overlapping datasets. Rhodes University's network of telescope sensors has continued to grow with additional network telescopes being brought online. At the time of writing, Rhodes University has a distributed network of five relatively small /24 network telescopes. With five network telescope sensors, this research focuses on comparative and correlation analysis of traffic activity across the network of telescope sensors. To aid summarisation and visualisation techniques, time series' representing time-based traffic activity, are constructed. By employing an iterative experimental process of captured traffic, two natural categories of the five network telescopes are presented. Using the cross- and auto-correlation methods of time series analysis, moderate correlation of traffic activity was achieved between telescope sensors in each category. Weak to moderate correlation was calculated when comparing category A and category B network telescopes' datasets. Results were significantly improved by studying TCP traffic separately. Moderate to strong correlation coefficients in each category were calculated when using TCP traffic only. UDP traffic analysis showed weaker correlation between sensors, however the uniformity of ICMP traffic showed correlation of traffic activity across all sensors. The results confirmed the visual observation of traffic relativity in telescope sensors within the same category and quantitatively analysed the correlation of network telescopes' traffic activity.

With the increasing pressures and concerns in education regarding capability, lifelong learning, higher order cognitive skills, transdisciplinary education and so on, educators are seeking fresh ways to teach and new tools to support that teaching. In South Africa, Outcomes Based Education (OBE) has identified critical outcomes (skills) across all subject areas such as problem solving, teamwork, fostering critical thinking etc. as a way of responding to these pressures and concerns. But OBE has been criticised for lacking the necessary tools to develop these critical skills and to promote cross-discipline learning. One innovative way of offering transformative teaching, instruction and learning that may foster the development of these critical skills, particularly those concerned with critical thinking, is by using geographic information systems (GIS) technologies. The scope for using these technologies in secondary education is now being realised for teaching the more generic, cross-discipline skills described whereby students are learning not only about GIS but also with GIS. This realisation provides the opportunity to create flexible, computer-based learning materials that are rooted in authentic, real-world contexts, which aim to enhance the cognitive skills of the students. If these technologies can be used in an innovative way to develop critical outcomes and skills, a model needs to be defined to aid the design and development of learning materials using these technologies for use in schools. The primary aim of this study has been to develop such a model; a model which emphasises the development of real-world learning materials that develop higher-order thinking skills in learners. Another key product of this study is the submission of a comprehensive yet flexible framework for evaluating instructional design models found in the educational literature in order to determine if these design models can be used to develop learning materials forparticular contexts.

Magister Scientiae - MSc / SIP is receiving much attention these days and it seems to be the most promising candidate as a signaling protocol for the current and future IP telephony services. Realizing this, there is the obvious need to provide a certain level of quality comparable to the traditional telephone service signalling system. Thus, we identified the major costs of SIP, which were found to be delay and security. This thesis discusses the costs of SIP, the solutions for the major costs, and the development of a low cost SIP application. The literature review of the components used to develop such a service is discussed, the networks in which the SIP is used are outlined, and some SIP applications and services previously designed are discussed. A simulation environment is then designed and implemented for the instant messaging service for wireless devices. This environment simulates the average delay in LAN and WLAN in different scenarios, to analyze in which scenario the system has the lowest costs and delay constraints. / South Africa

This thesis is a case study analysis of the dream one radio station had about creating something new and unique on the Internet. RadioSonderGrense (RSG), an Afrikaans South African radio station, saw opportunities for themselves as a radio station on the Internet and put enormous resources and man-power into their venture. Their vision of what the Internet could bring to their radio station, and what they could bring to a website set the ground for creative and innovative thought. This dissertation is an examination of whether the Internet lived up to the expectations RSG had for it, and whether they were able to use their resources (in terms of their audience, their advertisers and the uniqueness of radio) to create something new and never seen before. The foremost aim of this dissertation is to shed some light onto the up-to-now under researched area of why radio stations have begun to develop on the Internet. Through the analysis of RSG, their comes to this subject some new thoughts and ideas about the convergence of these two mediums. RSG, and radio in general, are examined historically, practically and in comparison to the Internet. This is done in order to fully grasp the project that RSG had set for themselves and to realize where they had come from and where they hoped to go. It is argued that although RSG had hoped for great things, their innovative thought was not enough to guarantee them their dreams. They were not able to fully utilize the resources available to them in combination with what the Internet could offer them to fulfill the expectations they had for themselves. The foremost conclusion is that although RSG were able to envisage what the Internet could add to the radio station, they fell short of giving their listeners, users and advertisers a tool which could make the RSG website truly unique. Their website gives the user some interesting and useful applications, but it does not make full use of what the Internet and radio together could create.

The Domain Name System (DNS), a name resolution protocol is one of the vulnerable network protocols that has been subjected to many security attacks such as cache poisoning, denial of service and the 'Kaminsky' spoofing attack. When DNS was designed, security was not incorporated into its design. The DNS Security Extensions (DNSSEC) provides security to the name resolution process by using public key cryptosystems. Although DNSSEC has backward compatibility with unsecured zones, it only offers security to clients when communicating with security aware zones. Widespread deployment of DNSSEC is therefore necessary to secure the name resolution process and provide security to the Internet. Only a few Top Level Domains (TLD's) have deployed DNSSEC, this inherently makes it difficult for their sub-domains to implement the security extensions to the DNS. This study analyses mechanisms that can be used by domains in islands of security to deploy DNSSEC so that the name resolution process can be secured in two specific cases where either the TLD is not signed or the domain registrar is not able to support signed domains. The DNS client side mechanisms evaluated in this study include web browser plug-ins, local validating resolvers and domain look-aside validation. The results of the study show that web browser plug-ins cannot work on their own without local validating resolvers. The web browser validators, however, proved to be useful in indicating to the user whether a domain has been validated or not. Local resolvers present a more secure option for Internet users who cannot trust the communication channel between their stub resolvers and remote name servers. However, they do not provide a way of showing the user whether a domain name has been correctly validated or not. Based on the results of the tests conducted, it is recommended that local validators be used with browser validators for visibility and improved security. On the DNS server side, Domain Look-aside Validation (DLV) presents a viable alternative for organizations in islands of security like most countries in Africa where only two country code Top Level Domains (ccTLD) have deployed DNSSEC. This research recommends use of DLV by corporates to provide DNS security to both internal and external users accessing their web based services. / LaTeX with hyperref package / pdfTeX-1.40.10

Telephony used to mean using a telephone to call another telephone on the Public Switched Telephone Network (PSTN), and data networks were used purely to allow computers to communicate. However, with the advent of the Internet, telephony services have been extended to run on data networks. Telephone calls within the IP network are known as Voice over IP. These calls are carried by a number of protocols, with the most popular ones currently being Session Initiation Protocol (SIP) and H.323. Calls can be made from the IP network to the PSTN and vice versa through the use of a gateway. The gateway translates the packets from the IP network to circuits on the PSTN and vice versa to facilitate calls between the two networks. Gateways have evolved and are now split into two entities using the master/slave architecture. The master is an intelligent Media Gateway Controller (MGC) that handles the call control and signalling. The slave is a "dumb" Media Gateway (MG) that handles the translation of the media. The current gateway control protocols in use are Megaco/H.248, MGCP and Skinny. These protocols have proved themselves on the edge of the network. Furthermore, since they communicate with the call signalling VoIP protocols as well as the PSTN, they have to be the lingua franca between the two networks. Within the VoIP network, the numbers of call signalling protocols make it difficult to communicate with each other and to create services. This research investigates the use of Gateway Control Protocols as the lowest common denominator between the call signalling protocols SIP and H.323. More specifically, it uses MGCP to investigate service creation. It also considers the use of MGCP as a protocol translator between SIP and H.323. A service was created using MGCP to allow H.323 endpoints to send Short Message Service (SMS) messages. This service was then extended with minimal effort to SIP endpoints. This service investigated MGCP’s ability to handle call control from the H.323 and SIP endpoints. An MGC was then successfully used to perform as a protocol translator between SIP and H.323.