1,720,961 research outputs found
Simulation of Economical Performance of Isolated Rural Mini-Grids
No full textPrior knowledge about the possible characteristics of demand and supply is vital in the planning and operation of economically sustainable isolated rural power systems. System modelling and simulation is one of the tools that can be used in planning and assessing the performance of these systems. This thesis is presenting a Monte Carlo simulation methodology for modelling, simulating and analysing the performance of isolated rural electricity markets applicable in developing countries. The definitions of possible power system operators managing these markets are introduced based on different economic objectives of operating the systems. The two system operators considered in the thesis are: altruistic and profit maximising operators. The concept used to define types of isolated rural electricity markets is combining the definitions of operators and the possible combinations of power supply options (purely thermal or hybrid system). It is anticipated that the rural electricity markets under consideration comprise of uncertainties in demand and supply (both demand and generation are modelled as random variables from assumed or estimated probability distributions). Demand is price sensitive and modelled as a product of two random variables, relative demand and peak demand. The price sensitivity of demand is shown by representing peak demand using an economic price-demand function. The parameters (price sensitivity and demand factor) of this function are modelled as random variables which reflect the randomness of consumers’ preferences. The simulation algorithm is based on the theory of correlated sampling, in order to compare the performance of systems under different operators. The thesis introduces the concept of nested Monte Carlo simulation to be able manage the simulation of different operators subjected to the same market conditions. The performance of electricity markets is assessed by analysing three parameters (tariffs, profit and reliability), which are random variables presented using probability distributions in form of duration curves. The methodology is tested on a theoretical case study system using load data obtained from a rural community in Africa. The case study illustrates how to use the model, preparation of the input variables and how to use the output to estimate and assess the possible performance of isolated rural power systems under different power system operators. It is anticipated that the proposed methodology can be used by researchers, planners and academia as a tool for planning, estimating and assessing the performance of rural power systems in isolated areas of developing countrie
Optimization of rural network development
No full textA huge area with enormous number of inhabitants isn’t electrified in Africa. Although the electricity generation and distribution technology is given, the speed of network development and construction is limited by financial, material and human resources. A short term decision has to be done where to develop the network that should fit also in the long term plans. On one hand the high voltage (HV) network can be developed step by step but in this case the remote territories will be electrified decades later and masses of people will migrate to the metropoles. It has huge financial and social costs as well. Another possibility to set up independent small scale microgrid-minigrid but it is not a competitor of the bulk net in large scale. It should be connected soon or later to the national grid. Mapping the problem to an optimization task we can find the optimal ratio between the bulk- and microgrid developments at a given resource constraints. We find that the HV network should reach the neighbouring areas meanwhile the microgrids should be set up at the fares region
The Role of Academia in Capacity Building for Sustainable Energy Development: The Case of Namibia
No full textAbstractEducation contributes to both short-term and long-term institutional building and supports human resource development. Both formal and informal education systems contribute to the development and dissemination of any technology. To ensure long-term sustainability and continuity of any sectorial development, professional, technical training and research at tertiary level (technical institutions, colleges and universities) should be given high priority. This paper proposes Capacity Building through education as a strategy towards Sustainable Energy Development. This approach allows the building of abilities, relationships and values that enable institutions, groups and individuals to improve the development, utilisation and performance of energy systems in an efficient and environmentally benign manner. Results from a project implemented by the Namibia University of Science and Technology in partnership with National University of Lesotho, Botswana University and Hochschule Darmstadt - University of Applied Sciences (Germany) are presented. The findings show that capacity building in the energy sector is still needed in the three partner countries (Namibia, Lesotho and Botswana). The proposed approaches to address the problem include: development of academic programmes and an energy repository. Though academic institutions are at the centre of capacity building in sustainable energy development, the success will depend on consorted and collaborative effort by all key stakeholder
Fortis Unum: Clustering mini-grid networks to widen energy access and enhance utility network resilience: Summaries of presentations at the 6th Africa Mini Grids Summit, Feb 2021
No full textThis document provides the summaries of the presentations given at the 6th Africa Mini Grid Summit held virtually from the 25th—26th February 2021 by the Energy & Climate Change Division and Sustainable Energy Research Group (SERG) as part of the Fortis Unum project. The content of the summaries provide a snapshot of the papers which are being produced by the academics and researchers within the University of Southampton (UK), Kyambogo University (Uganda), Jomo Kenyatta University of Agriculture and Technology (Kenya) and the Institute of Energy Studies and Research (Kenya)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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