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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Modelling of electricity cost risks and opportunities in the gold mining industry / Lodewyk Francois van der Zee

Van der Zee, Lodewyk Francois January 2014 (has links)
Carbon tax, increased reactive power charges, tariff increases and the Energy Conservation Scheme (ECS) are some of the worrying electricity cost risks faced by large South African industries. Some of these proposed cost risks are not enforced as yet, but once approved could threaten company financial viability and thousands of jobs. Managing multiple cost risks associated with electricity consumption at several mines can be laborious and complex. This is largely due to circumstantial rules related to each potential electricity cost risk and unique mine characteristic. To limit the electricity cost risks for a mining company, clear strategies and focus areas need to be identified. No literature was found that provides a simplified integrated electricity cost risk and mitigation strategy for the South African gold mining industry. Previous studies only focused on a single mine or mining subsystem. Literature pertaining to potential risks is available, however the exact impact and mitigation on the gold mining industry has yet to be determined. The aim of this study is to accurately predict the impact of electricity cost risks and identify strategies that could alleviate their cost implications. Electricity consumption and installed capacities were used to benchmark mines and categorise them according to investigated risks. The benchmarked results provided an accurate starting point to identify best practices and develop electricity cost saving strategies. This study will highlight the additional benefits that can be obtained by managing electricity usage for a group of mines or mining company. Newly developed models are used to quantify savings on pumping, compressed air and cooling systems. To manage and report on the potential risks and mitigation, an ISO 50001 based energy management system was developed and implemented. The applied and developed models can also be adjusted to review and manage the potential cost risks on other types of mines. Derived risk and mitigation models were further used to quantify the impact on one of the largest gold mining companies in South Africa. These models indicate a potential annual price increase of 12%, while mitigation strategies could reduce the electricity consumption by more than 7%. Mitigation savings resulted from proposed projects as well as behavioural change-induced savings due to improved management. Over a five-year period the projects identified could result in electricity costs savings of between R675-million and R819-million. / PhD (Electrical Engineering), North-West University, Potchefstroom Campus, 2014
222

Improving DSM project implementation and sustainability through ISO standards / Mariska van Heerden

Van Heerden, Mariska January 2014 (has links)
South African industries are challenged with above inflation electricity tariffs which may affect their competitiveness within their relative markets. In order to successfully manage these rising electricity costs and ensuing top market competition, a well organised demand side management (DSM) strategy must be implemented. Energy service companies (ESCos) have been assisting Eskom, South Africa’s leading electricity utility, in managing energy projects around the country. These DSM projects have introduced remarkable electricity and cost savings. However, the need for a sustainable energy management system (EnMS) within these projects does exist. This dissertation illustrates and discusses an EnMS designed to achieve maximum possible energy savings performances. The ISO 9 001 (quality management), ISO 14 001 (environmental management) and ISO 50 001 (energy management) standards were integrated for the development and implementation of this system. It provides a framework for project engineers and industrial clients to apply before, during and after project implementation. The use of the Plan-Do-Check-Act (PDCA) cycle will be applied throughout the dissertation. The PDCA cycle follows basic steps recommended by the relevant ISO standards. This cycle emphasises the concept of continual improvement. The developed EnMS was successfully implemented on various DSM projects. This selection includes previously maintained and new implemented projects. An analysis between the implementation and post- implementation performances supports the achieved results. The results of the case studies are presented in this dissertation. This dissertation illustrates that the continual improvement of an ISO based EnMS will result in a sustainable increase in electricity savings. An overall increase in project quality can be defined and measured according to the electricity consumptions and electricity cost savings. These electricity cost savings from the selected projects resulted to nearly R18 million during project implementation. A total amount of R52 million was already saved during the maintenance phase of 2014. This cost savings only reflect the results of the eight selected projects for the first eight months in 2014. The EnMS explained in this dissertation indicates that a continually controlled framework can improve the quality of DSM project implementation and sustainability. With the flexibility of changing the system according to impulsive constraints and client demands, the system can be used with various DSM projects. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
223

The implementation of a dynamic air compressor selector system in mines / Mattheus Hendrikus Pieters van Niekerk

Van Niekerk, Mattheus Hendrikus Pieters January 2015 (has links)
The generation of compressed air comprises 20% of the total electricity usage in the mining industry, although compressed air is often seen as a free source of energy. There are however significant costs associated with generating compressed air and maintaining a compressed air system. There are several methods to optimise the electricity used to generate compressed air. The focus of this study is on one of these methods – the implementation of a dynamic air compressor selector. A Dynamic Compressor Selector (DCS) system was developed to fulfil this purpose. DCS is a system that combines demand- and supply-side management of a compressed air network. DCS calculates a pressure set point for compressors and schedules the compressors according to the demand from the end-users. End-users include shafts, plants, workshops and smelters. DCS takes all of the compressors and end-users into consideration while doing the calculations. This dissertation focuses on the DCS implementation process and on the problems encountered by previous authors while implementing the DCS technology. Additional problems were encountered while the DCS technology was implemented. DCS was however still successfully implemented. This study will expand the implementation procedure to ensure that the technology can be implemented successfully in the future. DCS was implemented at a platinum mine in South Africa where it was able to calculate pressure set points for the compressors. DCS was able to accurately match the supply of, and demand for compressed air closely, resulting in lower overall compressed air usage. DCS improved compressor scheduling and control, limiting compressor cycling. Improved compressor scheduling and control resulted in significant decreases in the electricity used to generate compressed air at the mine. A target average evening peak clip of 2.197 MW was simulated, set and achieved. Evening peak clip power savings in excess of an average of 3 MW were achieved. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
224

An Incomplete Markets Explanation to the UIP Puzzle

Rabitsch, Katrin 03 1900 (has links) (PDF)
A large literature has related the failure of interest rate parity in the foreign exchange market to the existence of a time-varying risk premium. Nevertheless, most modern open economy DSGE models imply a (near) perfect interest rate parity condition. This paper presents a stylized two-country incomplete-markets model in which countries have strong precautionary motives because they face international liquidity constraints, the presence of which successfully generates a time-varying risk premium: the country that has accumulated debt after experiencing relative worse times has stronger precautionary motives and its asset carries a risk premium. (author's abstract) / Series: Department of Economics Working Paper Series
225

How Cutting the Cost of Using a Bank Affects Household’s Behavior of Remittance Transfers: Evidence From a Field Experiment in Rural Malawi

Lu, Chuyuan 01 January 2016 (has links)
Using a randomized experiment in rural Malawi, this paper finds that providing information on mobile bank buses’ services leads to a higher probability of adopting savings accounts in the treatment group. Households in the treated villages are 3.06 percentage points more likely to adopt savings accounts than households in the control group. Second, the information treatment leads to an increase of in the probability of households receiving remittances in the treated villages, as well as an increase in the amount of remittances received. In particular, the effect is strongest for households that lived at least three kilometers away from the trade centers, which suggests that the main cost of transferring remittance is the cost of traveling to a bank. Third, the 2SLS regression provides suggestive evidence that adopting savings accounts leads to an increase in households’ remittance activities. The 63.3 percentage points increase in the possibility of households receiving remittances after adopting savings accounts suggests that there previously exist high costs associated with the informal channels of transferring remittances.
226

Guideline for a robust assessment of the potential savings from water conservation and water demand management

Wegelin, Willem Adriaan 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Water loss in water distribution systems has been studied for many years in many countries and is continuously leading to the development of new concepts and theories, publications, guidelines and software models. Despite these developments, 45 % of water utilities in South Africa still do not understand the extent of water losses in the distribution systems that they operate (Wegelin et al., 2012:27). It is important, in terms of water services planning, that a realistic estimate of the potential savings from individual water conservation and water demand management (WC/WDM) measures is made as it impacts directly on water security and business matters. If the potential savings were incorrectly or inaccurately calculated, additional resources might have to be developed at short notice to be able to supply in the demand. Advanced software models, such as BENCHLEAK, PRESMAC, SANFLOW, AQUALITE and ECONOLEAK (McKenzie & Bhagwan, 2000) have been developed to quantify the extent of physical and commercial losses in water supply systems. Similar advanced models are available for estimating water demand. Such advanced models require numerous input parameters, each of which needs to be described accurately. The predicament is that such complex models are often simply not applicable in certain areas with limited resources and limited input data. In contrast, robust guidelines that are relatively insensitive to input parameters are useful in developing countries, where all input values for complex water demand models may be unavailable or inaccurate. No robust method has yet been developed for estimating the potential water savings that would result from WC/WDM interventions. A need thus exists to estimate water savings in a robust way with relatively few inputs. This guideline promotes the development of a robust WC/WDM strategy, based on a systematic and pragmatic approach, which requires less initial funding and develops with time. The methodologies developed by the Water Loss Task Force (WLTF) of the International Water Association (IWA), were used to develop six basic steps, which need to be followed to develop a WC/WDM strategy. During the six steps, the minimum requirements for implementing WC/WDM will be defined, the current water losses and efficiencies will be determined, and potential targets will be set based on national and international benchmarks. Once targets have been set, 20 key interventions were identified to address water use efficiency, and commercial and physical losses. The motivation behind each intervention is provided based on best practice, case studies and legal requirements. The model ensures that the potential savings from the various interventions are sufficient to ensure that targets are achieved, and if not, that targets must be revised. The potential savings from interventions are based on literature reviews and new formulas developed as part of this guideline. The results from the various interventions would enable the water utility to prioritise interventions. The guideline concludes with a flow diagram describing the methodology.
227

Three essays in macroeconomics and financial economics

Oduncu, Arif 19 August 2010 (has links)
In the first chapter, I analyze the question that whether the elasticity of intertemporal substitution or risk aversion is more important determinant of precautionary savings. This is an important question since a significant fraction of the capital accumulation is due to precautionary savings according to studies. Thus, knowing the important determinant of precautionary savings will be helpful to understand the capital accumulation mechanism. I look into the effects of the elasticity of intertemporal substitution and risk aversion on precautionary savings separately by performing simulations in order to obtain numerical results. I find that the elasticity of intertemporal substitution is more important determinant than risk aversion. In the second chapter, I study the impact of the introduction of futures trading on the volatility of the underlying spot market for Turkish Istanbul Stock Exchange (ISE).The economic literature intensified the debate on the negative or positive impact of futures trading on the stock market volatility. Although there are empirical studies for different countries with mixed results, most of them focus on developed countries. There are a few empirical researches on emerging markets. Analyzing the data, following results are obtained for ISE. First, the results suggest that the introduction of futures trading has decreased the volatility of ISE. Second, the results show that futures trading increases the speed at which information is impounded into spot market prices. Third, the asymmetric responses of volatility to the arrival of news for ISE have increased after the introduction of futures trading. In the third chapter, I investigate the presence of calendar anomalies in ISE by using GARCH models. The presence of calendar anomalies and their persistence presence since their first discovery still remains a puzzle to be solved. On the other hand, there are some claims that general anomalies are much less pronounced after they became known to the public. Most of the studies have examined the developed financial markets. However, it is important to test the calendar effects in data sets that are different from those in which they are originally discovered and so ISE is a good case to test the calendar effects for a developing country. / text
228

行為財務架構下的退休商品設計機制 / Keep golden years golden: a behavioral framework for retirement savings product design

歐怡君, Ou, Yi-Chun Unknown Date (has links)
退休規劃對個人或社會一直以來都是重要的議題。但是大部分的人往往受到心理偏誤的影響,逐漸偏離原本的目標。本研究除了檢視現行台灣地區實施的退休金制度外,也探討退休時可能面臨的各種風險及世界銀行建議之最適宜退休金制度,並發現在進行退休規劃時個人準備是不可缺少的。此外,本研究進一步釐清在退休規劃時會受到哪些心理偏誤的影響,以及這些心理偏誤會如何影響退休規劃。當退休規劃納入心理偏誤的影響後,對提供投資計畫的金融機構,應加入哪些機制才能消除因為投資人心理偏誤導致投資績效不佳的後果,期望能成功的協助投資人達成退休規劃的目標。最後,本文也討論了退休規劃建議採用的標的資產及退休商品的行銷策略。 / Retirement Savings has been an important issue for people, but most of them will deviate from their goals due to some psychological biases. In this paper, the present situation of Taiwanese pension system has been reviewed. Through analyzing the appropriate retirement system and considering the risks that people will face during the retirement, the paper points out the importance of self preparation. In addition, this paper conclude certain psychological biases that will influence retirement savings and give the alternatives of retirement savings program design to inform the financial institution in retirement plan promotion. Meanwhile, the propositions of underlying assets and marketing strategies are also provided in the research.
229

An investigative analysis into the saving behaviour of poor households in developing countries: with specific reference to South Africa.

Nga, Marie-Therese January 2007 (has links)
<p>In South Africa, as in many developing countries, most households are poor and do not save, as a result of which they do not acquire any positive net worth and which also constrains access to formal means of finance. South Africa is a consuming nation, with increasing ratios of household consumption resulting in dissaving and often unsustainable levels of household debt, which is also stimulated by the current lower level of interest rates. This situation is worse amongst poorhouseholds who also often experience financial shocks, for instance because of the death of family membersas a result of HIV/AIDS. This report provided an overview of household saving in South Africa for the period 1983 to 2003. It identified the main factors responsible for the lack of a commitment to saving which are particularly relevant in the case of poor households.</p>
230

Clinical Indicators that Predict Readmission Risk in Patients with Acute Myocardial Infarction, Heart Failure, and Pneumonia

Chen, Weihua 28 April 2017 (has links)
A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / BACKGROUND: In order to improve the quality and efficacy of healthcare while reducing the overall cost to deliver that healthcare, it has become increasingly important to manage utilization of services for populations of patients. Healthcare systems are aggressively working to identify patients at risk for hospital readmissions. Although readmission rates have been studied before, parameters for identifying patients at risk for readmission appear to vary depending the patient population. We will examine existing Electronic Health Record (EHR) data at Banner Health to establish what parameters are clinical indicators for readmission risk. Three conditions were identified by the CMS to have high and costly readmissions rates; heart failure (HF), acute myocardial infarction (AMI), and pneumonia. This study will focus on attempting to determine the primary predictive variables for these three conditions in order to have maximum impact on cost savings. METHODS: A literature review was done and 68 possible risk variables were identified. Of these, 30 of the variables were identifiable within the EHR system. Inclusion criteria for individual patient records are that they had an index admission secondary to AMI, heart failure, or pneumonia and that they had a subsequent readmission within 30 days of the index admission. Pediatric populations were not studied since they have unique factors for readmission that are not generalizable. Logistics regression was applied to all data including data with missing data rows. This allowed all coefficients to be interpreted for significance. This model was termed the full model. Variables that were determined to be insignificant were subsequently removed to create a new reduced model. Chi square testing was then done to compare the reduced model to the full model to determine if any significant differences existed between the two. RESULTS: Several variables were determined to be the significant predictors of readmission. The final reduced model had 19 predictors. When analyzed using ROC analysis, the area under the curve (AUC) was 0.64. CONCLUSION: Several variables were identified that could be significant contributors to readmission risk. The final model had an AUC on it ROC of 0.64 suggesting that it would only have poor to moderate clinical value for predicting readmission.

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