This study dealt with the issue of sustainability of ICT4D initiatives being a problem with few success stories (Heeks, 2002, Toyama, 2010). Many of these initiatives were planned and executed in a top-down fashion by large funders and governments, and these failures have stimulated the search for new strategies to achieve long-term sustainability. One possible approach is to consider the different levels of systems that are involved. The reasons for failure lie inside the scope of a project, within the community itself, and outside the community in the larger socio-economic system which includes the economy. A systems approach with respect to the analysis of the sustainability (or lack thereof) of development initiatives was therefore adopted. The Choice Framework of Dorothea Kleine (2010) was used since it is a systemic approach, developed in the study of ICT4D initiatives, that embraces the complexity of engaging with development paradigms, societal structures and personal agency. The research was done on a large South African government initiative, the Broadband-for-All (BB4All), community-based wireless mesh network project which aimed to provide a cost-effective way of enabling reliable broadband connectivity in rural areas. The project had two key aspects, the provision of a large-scale demonstrator of a wireless mesh network (WMN) as a broadband solution and the establishment of a Village Operator (VO) model to support access to and increase the use of the technology. The teachers and learners in more than 170 schools were the primary customers. Young people from local communities were trained as VOs to become local entrepreneurs (micro-enterprises) responsible for operating and supporting the BB4All service in their assigned cluster of schools and respective communities. The research focus was the sustainability of the VOs. The Choice Framework was used to provide a context for the research regarding the role played by social resources (social capital) in contributing to the sustainability of the VO micro-enterprises. In-depth interviews were held with all but one of the 15 VOs in order to develop an understanding of their social capital and the influence thereof on them as entrepreneurs. The importance and usefulness of social capital in supporting sustainability at VO and initiative level was analysed. Three major themes emerged that were analysed in detail, namely, the role of social capital, community service and social entrepreneurship, as well as the development of networks of innovation. At a theoretical level, the research reflected on implications of the findings for the role of social capital in the Choice Framework. At a practical level, considerations for using a social capital perspective in order to improve the conceptualisation, design, implementation and transfer of ICT4D initiatives for sustainability were developed. / Thesis (PhD)--University of Pretoria, 2016. / Informatics / PhD / Unrestricted

Airplanes have different ways to connect to the ground, including satellite air-to-ground communication (SA2GC) and direct air-to-ground communication (DA2GC). Each connection/link offers a different varying amount of transmission capacity over flight time. The traffic generated in the airplane must be forwarded/sent to ground over the available links. It is however not clear how the traffic should be forwarded so that traffic quality of service (QoS) requirements are met. The thesis at hand considers this question, and implements an algorithm handling the forwarding decision with three different forwarding schemes. Those consider traffic parameters in calculating a value assigned to each traffic flow, over a combination of priority, delay requirement and the number of times a traffic flow is dropped. The forwarding algorithm relies on proposed in-flight broadband connectivity (IFBC) network traffic and air-to-ground (A2G) link models, which aim at approximating the network environment of future IFBC networks. It is shown that QoS requirements of traffic flows in terms of packet loss and delay cannot be satisfied with capacities offered by current DA2GC and SA2GC technology. For a future scenario, with higher assumed link capacities, the QoS requirements are met to a higher extent. This is shown in lower packet loss and delay experienced by the respective traffic flows. Further, it is shown that the performance can be improved with specific forwarding schemes used by the forwarding algorithm. It is also investigated how a web cache can be used as a fallback technology. For this a required web cache hit rate is found, which should be high enough to offload the network with content served from the cache. Overall, the thesis aims at proposing an efficient traffic forwarding technique, and at giving insight into an alternative if this technique fails. / Flygplan har olika sätt att ansluta till marken, inklusive satellit-mark-kommunikation (SA2GC) och direkt luft till markkommunikation (DA2GC). Varje anslutning/länk erbjuder en annan varierande mängd överföringskapacitet under flygtid. Den trafik som genereras i flygplanet måste vidarebefordras/skickas till marken över de tillgängliga länkarna. Det är emellertid inte klart hur trafiken ska vidarebefordras så att trafiksäkerhetskvaliteten (QoS) uppfylls. Avhandlingen handlar om denna fråga och implementerar en algoritm som hanterar vidarebefordringsbeslutet med tre olika vidarebefordringssystem. De betraktar trafikparametrar vid beräkning av ett värde som tilldelas varje trafikflöde, över en kombination av prioritet, fördröjningskrav och antalet gånger ett trafikflöde tappas. Vidarebefordringsalgoritmen är beroende av föreslagna bredbandsförbindelser (IFBC) i nätverk och A2G-länkmodeller, som syftar till att approximera nätverksmiljön för framtida IFBC-nätverk. Det visas att QoS-krav på trafikflöden när det gäller paketförlust och fördröjning inte kan tillgodoses med kapacitet som erbjuds av nuvarande DA2GC- och SA2GC-teknik. För ett framtida scenario, med högre antagna länkkapacitet, uppfylls QoS-kraven i högre utsträckning. Detta visas med lägre paketförlust och fördröjning som upplevs av respektive trafikflöden. Vidare är det visat att prestanda kan förbättras med specifika vidarekopplingsscheman som används av vidarebefordringsalgoritmen. Det undersöks också hur en webbcache kan användas som en återgångsteknik. För detta hittas en obligatorisk webbcache-träfffrekvens, som bör vara tillräckligt hög för att ladda upp nätverket med innehåll som serveras från cacheminnet. Sammanfattningsvis syftar uppsatsen till att föreslå en effektiv trafiköverföringsteknik och att ge insikt om ett alternativ om denna teknik misslyckas.