187 resultados para Agriculture--South Africa--Maps
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Power system stabilizers (PSS) work well at the particular network configuration and steady state conditions for which they were designed. Once conditions change, their performance degrades. This can be overcome by an intelligent nonlinear PSS based on fuzzy logic. Such a fuzzy logic power system stabilizer (FLPSS) is developed, using speed and power deviation as inputs, and provides an auxiliary signal for the excitation system of a synchronous motor in a multimachine power system environment. The FLPSS's effect on the system damping is then compared with a conventional power system stabilizer's (CPSS) effect on the system. The results demonstrate an improved system performance with the FLPSS and also that the FLPSS is robust
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This paper investigates the control of a HVDC link, fed from an AC source through a controlled rectifier and feeding an AC line through a controlled inverter. The overall objective is to maintain maximum possible link voltage at the inverter while regulating the link current. In this paper the practical feedback design issues are investigated with a view of obtaining simple, robust designs that are easy to evaluate for safety and operability. The investigations are applicable to back-to-back links used for frequency decoupling and to long DC lines. The design issues discussed include: (i) a review of overall system dynamics to establish the time scale of different feedback loops and to highlight feedback design issues; (ii) the concept of using the inverter firing angle control to regulate link current when the rectifier firing angle controller saturates; and (iii) the design issues for the individual controllers including robust design for varying line conditions and the trade-off between controller complexity and the reduction of nonlinearity and disturbance effects
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The design and implementation of a high-power (2 MW peak) vector control drive is described. The inverter switching frequency is low, resulting in high-harmonic-content current waveforms. A block diagram of the physical system is given, and each component is described in some detail. The problem of commanded slip noise sensitivity, inherent in high-power vector control drives, is discussed, and a solution is proposed. Results are given which demonstrate the successful functioning of the system
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Balancing between the provision of high quality of service and running within a tight budget is one of the biggest challenges for most metro railway operators around the world. Conventionally, one possible approach for the operator to adjust the time schedule is to alter the stop time at stations, if other system constraints, such as traction equipment characteristic, are not taken into account. Yet it is not an effective, flexible and economical method because the run-time of a train simply cannot be extended without limitation, and a balance between run-time and energy consumption has to be maintained. Modification or installation of a new signalling system not only increases the capital cost, but also affects the normal train service. Therefore, in order to procure a more effective, flexible and economical means to improve the quality of service, optimisation of train performance by coasting point identification has become more attractive and popular. However, identifying the necessary starting points for coasting under the constraints of current service conditions is no simple task because train movement is attributed by a large number of factors, most of which are non-linear and inter-dependent. This paper presents an application of genetic algorithms (GA) to search for the appropriate coasting points and investigates the possible improvement on computation time and fitness of genes.
Building a methodology for context-aware business processes: insights from an exploratory case study
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This paper describes the findings derived from an exploratory case study into the business processes at a leading Australian insurance provider. The business processes are frequently subjected to changes and deviations due to contextual events such as weather, financial conditions and others. In this study, we examine how context impacts business processes and how resulting business process changes are enacted. From our analysis, we suggest a methodological framework to guide organisations in the complex challenge of linking changing contextual factors with internal process design.
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"International Journalism and Democracy" explores a new form of journalism that has been dubbed ‘deliberative journalism’. As the name suggests, these forms of journalism support deliberation — the processes in which citizens recognize and discuss the issues that affect their communities, appraise the potential responses to those issues, and make decisions about whether and how to take action. Authors from across the globe identify the types of journalism that assist deliberative politics in different cultural and political contexts. Case studies from 15 nations spotlight different approaches to deliberative journalism, including strategies that have been sometimes been labeled as public or civic journalism, peace journalism, development journalism, citizen journalism, the street press, community journalism, social entrepreneurism, or other names. Countries that are studied in-depth include the United States, the United Kingdom, Germany, Finland, China, India, Japan, Indonesia, Australia, New Zealand, South Africa, Nigeria, Brazil, Colombia and Puerto Rico. Each of the approaches that are described offers a distinctive potential to support deliberative democracy. However, the book does not present any of these models or case studies as examples of categorical success. Instead, it explores different elements of the nature, strengths, limitations and challenges of each approach, as well as issues affecting their longer-term sustainability and effectiveness. The book also describes the underlying principles of deliberation, the media’s potential role in deliberation from a theoretical and practical perspective, and ongoing issues for deliberative media practitioners.
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Since 2005, Business Process Management (BPM) has been one of the top 10 issues for CIO’s. However, while there is a general awareness what BPM is and what it relates to, one needs to ask ‘does everyone have the same understanding of the BPM phenomenon? And if not, is there a pattern to these conceptions and how do the ways of conceptualizing BPM differ?’ This paper presents the practitioner conceptions of BPM using a phenomenographic approach to detect variations in the BPM conceptions emphasised. 26 interviews were conducted with BPM practitioners with various scopes of work (namely program management, project management and execution levels) in this qualitative research. Distinct variations in how BPM is conceptualized among BPM practitioners are revealed, showing that emphasis is put depending on their scope of work either towards value generation, improvement or managing processes. This is of particular relevance to the Information Systems and BPM community in order to align the rigorous work done to date by the research community with the current understanding of BPM in the practitioner community.
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Research in structural dynamics has received considerable attention due to problems associated with emerging slender structures, increased vulnerability of structures to random loads and aging infrastructure. This paper briefly describes some such research carried out on i) dynamics of composite floor structure, ii) dynamics of cable supported footbridge, iii) seismic mitigation of frame-shear wall structure using passive dampers and iv) development of a damage assessment model for use in structural health modelling.
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There is conflicting evidence in the literature with respect to backpackers as contributors to sustainable travel. This paper explores this market with respect to sustainable travel attitudes, behaviours and preferences. More specifically it examined the motivations of backpacker visitors to Australia, their preferences for environmentally friendly and volunteer tourism experiences, and explored attitudes towards the influence of environmental impacts on the future of travel. The resultsindicate that not all backpackers necessarily have a strong focus on the sustainability of their travel, but that those interested in community and environmental volunteering have the greatest potential to make meaningful contributions.
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This case study explored how a group of primary school teachers in Papua New Guinea (PNG) understood Outcomes-based Education (OBE). OBE measures students. learning against specific outcomes. These outcomes are derived from a country.s vision of the kind of citizen that the education system should produce. While countries such as Australia, South Africa, New Zealand and the United States have abandoned OBE, others such as PNG have adopted it in various ways. How teachers understand OBE in PNG is important because such understandings are likely to influence how they implement the OBE curriculum. There has been no research to date which has investigated PNG primary school teachers. understandings and experiences with OBE. This study used a single exploratory case study design to investigate how twenty primary school teachers from the National Capital District (NCD) in PNG understood OBE. The study, underpinned by an intepretivist paradigm, explored the research question: How do primary school teachers understand outcomes-based education in PNG? The data comprised surveys, in-depth interviews and documents. Data were analysed thematically and using explanation building techniques. The findings revealed that OBE is viewed by teachers as a way to equip them with additional strategies for planning and programming, teaching and learning, and assessment. Teachers also described how OBE enabled both students and teachers to become more engaged and develop positive attitudes towards teaching and learning. There was also a perception that OBE enhanced students. future life skills through increased local community support. While some teachers commented on how the OBE reforms provided them with increased professional development opportunities, the greatest impediment to implementing OBE was perceived to be a lack of sufficient teaching and learning resources. The process of planning and programming classroom activities was also regarded as onerous. Some teachers indicated that they had been required to implement OBE without adequate in-service training support. The social constructivist theory of knowledge which underpins OBE.s student-centred pedagogy can cause tensions within PNG.s cultural contexts of teaching and learning. Teachers need to be aware of these tensions when conducting peer or group learning under OBE in PNG. By exploring how these PNG primary teachers understood OBE, the study highlighted how teachers engaged with OBE concepts when interpreting syllabus documents and how they applied these concepts to curriculum. Identifying differences in teacher understanding of OBE provides guidance for both the design of materials to support the implementation of OBE and for the design of in-service training. Thus, the outcomes of this study will inform educators about the implementation of OBE in PNG. In addition, the outcomes will provide much needed insight into how a mandated curriculum and pedagogical reform impacts teachers‟ practices in PNG.
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As the development of ICD-11 progresses, the Australian Bureau of Statistics is beginning to consider what will be required to successfully implement the new version of the classification. This paper will present early thoughts on the following: building understanding amongst the user community of upcoming changes and the implications of those changes; the need for training of coders and data users; development of analytical methods and conduct of comparability studies; processes to test, accept and implement new or updated coding software; assessment of coding quality; changes to data analyses and reporting processes; updates to regular publications; and assessing the resources required for successful implementation.
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The number of doctorates being awarded around the world has almost doubled over the last ten years, propelling it from a small elite enterprise into a large and ever growing international market. Within the context of increasing numbers of doctoral students this book examines the new doctorate environment and the challenges it is starting to face. Drawing on research from around the world the individual authors contribute to a previously under-represented focus of theorising the emerging practices of doctoral education and the shape of change in this arena. Key aspects, expertly discussed by contributors from the UK, USA, Australia, New Zealand, China, South Africa, Sweden and Denmark include: -the changing nature of doctoral education -the need for systematic and principled accounts of doctoral pedagogies -the importance of disciplinary specificity -the relationship between pedagogy and knowledge generation -issues of transdisciplinarity. Reshaping Doctoral Education provides rich accounts of traditional and more innovative pedagogical practices within a range of doctoral systems in different disciplines, professional fields and geographical locations, providing the reader with a trustworthy and scholarly platform from which to design the doctoral experience. It will prove an essential resource for anyone involved in doctorate studies, whether as students, supervisors, researchers, administrators, teachers or mentors.
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A crucial contemporary policy question for governments across the globe is how to cope with international crime and terrorist networks. Many such “dark” networks—that is, networks that operate covertly and illegally—display a remarkable level of resilience when faced with shocks and attacks. Based on an in-depth study of three cases (MK, the armed wing of the African National Congress in South Africa during apartheid; FARC, the Marxist guerrilla movement in Colombia; and the Liberation Tigers of Tamil Eelam, LTTE, in Sri Lanka), we present a set of propositions to outline how shocks impact dark network characteristics (resources and legitimacy) and networked capabilities (replacing actors, linkages, balancing integration and differentiation) and how these in turn affect a dark network's resilience over time. We discuss the implications of our findings for policymakers.
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This paper explores violent urbanism in the recent science-fiction filem District 9 whhich depicts an alien immigration camp, filmed on location in Soweto in 2008 in the midst of a series of violent clashed between indigenous South Africans and the new wave of African immigrants. Violent Urbanism is the State of method of control of bodies and populations by those precise biological techniques that determine geopolitical sites for the control of cities. This film while presented as cinema verite speaks the real invasion of traditional, spatio-disciplinary regimes such as corporate-run detention centres, refugee camps, border control and enforced relocation by those imperceptible techniques which violate the body by reducing it to a biological datum, tool, or specimen to serve the security agenda of the twenty-first century nation-state. These techniques are chemical and biological warfare proliferation; genetic engineering; and surveillance systems, such as biometrics, whose purview is no longer limited to the specular but includes the molecular. District 9 evinces a compelling urban image of contemporary biopolitics that disturbs the received historiography of post-apartheid urbanism. Clearly Johannesburg is not the only place this could or is happening - the reach of biopolitics is worldwide. District 9 visualises with utter precision the corporate hijacking of the biological realm in contemporary cites, just as it asks the unsettling question, who exactly is the "audience" of Violent Urbanism?