848 resultados para Agriculture--South Africa--Maps
Resumo:
The Mobile Learning Kit is a new digital learning application that allows students and teachers to compose, publish, discuss and evaluate their own mobile learning games and events. The research field was interaction design in the context of mobile learning. The research methodology was primarily design-based supported by collaboration between participating disciplines of game design, education and information technology. As such, the resulting MiLK application is a synthesis of current pedagogical models and experimental interaction design techniques and technologies. MiLK is a dynamic learning resource for incorporating both formal and informal teaching and learning practices while exploiting mobile phones and contemporary digital social tools in innovative ways. MiLK explicitly addresses other predominant themes in educational scholarship that relate to current education innovation and reform such as personalised learning, life-long learning and new learning spaces. The success of this project is indicated through rigorous trials and actual uptake of MiLK by international participants in Australia, UK, US and South Africa. MiLK was awarded for excellence in the use of emerging technologies for improved learning and teaching as a finalist (top 3) in the Handheld Learning and Innovation Awards in the UK in 2008. MiLK was awarded funding from the Australasian CRC for Interaction Design in 2008 to prepare the MiLK application for development. MiLK has been awarded over $230,000 from ACID since 2006. The resulting application and research materials are now being commercialised by a new company, ‘ACID Services’.
Resumo:
Ecological problems are typically multi faceted and need to be addressed from a scientific and a management perspective. There is a wealth of modelling and simulation software available, each designed to address a particular aspect of the issue of concern. Choosing the appropriate tool, making sense of the disparate outputs, and taking decisions when little or no empirical data is available, are everyday challenges facing the ecologist and environmental manager. Bayesian Networks provide a statistical modelling framework that enables analysis and integration of information in its own right as well as integration of a variety of models addressing different aspects of a common overall problem. There has been increased interest in the use of BNs to model environmental systems and issues of concern. However, the development of more sophisticated BNs, utilising dynamic and object oriented (OO) features, is still at the frontier of ecological research. Such features are particularly appealing in an ecological context, since the underlying facts are often spatial and temporal in nature. This thesis focuses on an integrated BN approach which facilitates OO modelling. Our research devises a new heuristic method, the Iterative Bayesian Network Development Cycle (IBNDC), for the development of BN models within a multi-field and multi-expert context. Expert elicitation is a popular method used to quantify BNs when data is sparse, but expert knowledge is abundant. The resulting BNs need to be substantiated and validated taking this uncertainty into account. Our research demonstrates the application of the IBNDC approach to support these aspects of BN modelling. The complex nature of environmental issues makes them ideal case studies for the proposed integrated approach to modelling. Moreover, they lend themselves to a series of integrated sub-networks describing different scientific components, combining scientific and management perspectives, or pooling similar contributions developed in different locations by different research groups. In southern Africa the two largest free-ranging cheetah (Acinonyx jubatus) populations are in Namibia and Botswana, where the majority of cheetahs are located outside protected areas. Consequently, cheetah conservation in these two countries is focussed primarily on the free-ranging populations as well as the mitigation of conflict between humans and cheetahs. In contrast, in neighbouring South Africa, the majority of cheetahs are found in fenced reserves. Nonetheless, conflict between humans and cheetahs remains an issue here. Conservation effort in South Africa is also focussed on managing the geographically isolated cheetah populations as one large meta-population. Relocation is one option among a suite of tools used to resolve human-cheetah conflict in southern Africa. Successfully relocating captured problem cheetahs, and maintaining a viable free-ranging cheetah population, are two environmental issues in cheetah conservation forming the first case study in this thesis. The second case study involves the initiation of blooms of Lyngbya majuscula, a blue-green algae, in Deception Bay, Australia. L. majuscula is a toxic algal bloom which has severe health, ecological and economic impacts on the community located in the vicinity of this algal bloom. Deception Bay is an important tourist destination with its proximity to Brisbane, Australia’s third largest city. Lyngbya is one of several algae considered to be a Harmful Algal Bloom (HAB). This group of algae includes other widespread blooms such as red tides. The occurrence of Lyngbya blooms is not a local phenomenon, but blooms of this toxic weed occur in coastal waters worldwide. With the increase in frequency and extent of these HAB blooms, it is important to gain a better understanding of the underlying factors contributing to the initiation and sustenance of these blooms. This knowledge will contribute to better management practices and the identification of those management actions which could prevent or diminish the severity of these blooms.
Resumo:
Contemporary urban form, particularly in the cities of South Africa, lacks distinction and quality. The majority of developments are conceived as private and dislocated initiatives, surveiled enclaves with gated access being the only conduit to the outside world. Any concern for a positive contribution to the matrix of public activity is seldom a consideration. The urban form responds to the perception that traffic systems are paramount to the successful flux of the city in satisfying the escalating demands of vehicular movement. In contrast many of the urban centres around the world, the great historical centres of Europe, Americas and the Sub-Continent are admired and considered the ultimate models in urban experience. The colonnades, bazaars and boulevards hosting an abundance of street activity are the characteristics of such centres and are symptomatic of a city growth based on pedestrian movement patterns, an urbanism supportative of human interaction and exchange, a form which has nurtured the existence of a public realm. Through the understanding of the principles of traditional urbanism we may learn that the modernist paradigm of a contemporary suburbia has resulted in disconnected and separate land uses with isolated districts where a reliance on the car is essential rather than optional.
Resumo:
The most costly operations encountered in pairing computations are those that take place in the full extension field Fpk . At high levels of security, the complexity of operations in Fpk dominates the complexity of the operations that occur in the lower degree subfields. Consequently, full extension field operations have the greatest effect on the runtime of Miller’s algorithm. Many recent optimizations in the literature have focussed on improving the overall operation count by presenting new explicit formulas that reduce the number of subfield operations encountered throughout an iteration of Miller’s algorithm. Unfortunately, almost all of these improvements tend to suffer for larger embedding degrees where the expensive extension field operations far outweigh the operations in the smaller subfields. In this paper, we propose a new way of carrying out Miller’s algorithm that involves new explicit formulas which reduce the number of full extension field operations that occur in an iteration of the Miller loop, resulting in significant speed ups in most practical situations of between 5 and 30 percent.
Resumo:
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
Resumo:
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
Resumo:
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
Resumo:
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
Resumo:
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.
Resumo:
"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.
Resumo:
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.
Resumo:
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.
Resumo:
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.