56,030 research outputs found

    A survey of self organisation in future cellular networks

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    This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks

    Toward an efficient solution for dynamic ad hoc network interoperability

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    An ad hoc network is formed by an impromptu grouping of network capable nodes. The nodes forming the network have unconstrained mobility, and so provide a dynamic network topology. Current work in this research area has focused on designing routing protocols capable of efficiently forwarding packets in these dynamic network environments. This has led to several designs for ad hoc routing protocols based on various routing algorithms, each suited to specific usage characteristics. This paper will discuss issues relating to routing in ad hoc networks. We will describe an active networking based solution that provides dynamic routing protocol interoperability and enables migration of nodes between ad hoc groups. Our design is motivated by a squad and base scenario which consists of two groups wishing to communicate. These groups have contrasting deployment characteristics and so use different routing protocols

    No. 22: South African Government and Civil Society Responses to Zimbabwean Migration

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    This policy brief discusses a key paradox in relation to Zimbabwean migration into South Africa. While Zimbabwean migration since 2000 has been the largest concentrated flow in South African history, South Africa’s reaction to this movement has been characterised by the attempt to continue with ‘business as usual’ and ‘no crisis’ responses.1 Compared with most other developed and developing countries, where an inflow of tens or hundreds of thousands of people is usually treated as a political crisis, such a non-response to over a million immigrants requires explanation. The lack of commensurate responses is especially noticeable within the various departments of the South African government, but also within much of organised civil society. The scale and range of responses has addressed neither the scale nor the specific nature of Zimbabwean migration.2 In practice, therefore, addressing migrant needs and migration impacts is left to social networks among Zimbabweans, (often poor) South African citizens and local level public service providers such as local clinics. As a result of this fragmented and inadequate set of responses there are two major gaps: firstly between the needs of Zimbabwean migrants and the formal institutional frameworks and services provided to them, and secondly between the impacts of Zimbabwean migration on South African society and its ability to manage these impacts. There has been increasing documentation of Zimbabwean migrants’ welfare needs in South Africa (Bloch 2005; Zimbabwe Torture Victims Project 2005; Makina 2007; CoRMSA 2008; Human Rights Watch 2008). However, in parallel to the lack of coherent government and civil society responses to Zimbabwean migration, there has been a relative dearth of academic or think-tank documentation or analysis of these responses, and indeed of the implications of non-response for South Africa (Polzer 2008). Crucially, there has been no serious research on the dispersed and privatised responses by Zimbabwean networks and South African citizens, even though the aggregate impact of these actors is likely to be at least as significant, if not more so, than formal responses

    GRIDKIT: Pluggable overlay networks for Grid computing

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    A `second generation' approach to the provision of Grid middleware is now emerging which is built on service-oriented architecture and web services standards and technologies. However, advanced Grid applications have significant demands that are not addressed by present-day web services platforms. As one prime example, current platforms do not support the rich diversity of communication `interaction types' that are demanded by advanced applications (e.g. publish-subscribe, media streaming, peer-to-peer interaction). In the paper we describe the Gridkit middleware which augments the basic service-oriented architecture to address this particular deficiency. We particularly focus on the communications infrastructure support required to support multiple interaction types in a unified, principled and extensible manner-which we present in terms of the novel concept of pluggable overlay networks

    A European research agenda for lifelong learning

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    It is a generally accepted truth that without a proper educational system no country will prosper, nor will its inhabitants. With the arrival of the post-industrial society, in Europe and elsewhere, it has become increasingly clear that people should continue learning over their entire life-spans lest they or their society suffer the dire consequences. But what does this future lifelong learning society exactly look like? And how then should education prepare for it? What should people learn and how should they do so? How can we afford to pay for all this, what are the socio-economic constraints of the move towards a lifelong-learning society? And, of course, what role can and should the educational establishment of schools and universities play? This are questions that demand serious research efforts, which is what this paper argues for

    Formative evaluation of the Applied Educational Research Scheme (AERS)

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    Mobile Ad-Hoc Networks

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    Ad-hoc networks are a key in the evolution of wireless networks. Ad-hoc networks are typically composed of equal nodes, which communicate over wireless links without any central control. Ad-hoc wireless networks inherit the traditional problems of wireless and mobile communications, such as bandwidth optimisation, power control and transmission quality enhancement. In addition, the multi-hop nature and the lack of fixed infrastructure brings new research problems such as configuration advertising, discovery and maintenance, as well as ad-hoc addressing and self-routing. Many different approaches and protocols have been proposed and there are even multiple standardization efforts within the Internet Engineering Task Force, as well as academic and industrial projects. This chapter focuses on the state of the art in mobile ad-hoc networks. It highlights some of the emerging technologies, protocols, and approaches (at different layers) for realizing network services for users on the move in areas with possibly no pre-existing communications infrastructure
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