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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.
1

A critical review of Operations Excellence programs : a petrochemical company as case study / Neeven Govindsamy

Govindsamy, Neeven January 2014 (has links)
Operations improvement methodologies have been adopted by manufacturing companies since the early 20th century. Japanese manufacturers were able to offer products of high quality and efficient production costs through systems such as Lean. Manufacturers in the West soon adopted systems of their own thereafter. Operations Excellence is a generic term used to describe such systems, and can be described as a management system delivering competitiveness through the continuous improvement of operational performance. This study provides a critical review of the implementation of an Operations Excellence program by examining the system adopted by a petrochemical company in South Africa. The review allowed the implementation shortcomings to be identified so that resolutions could be suggested, thus facilitating successful utilisation of the system. An evaluation of Operations Excellence programs utilised globally and at the case study organisation was carried out as part of a literature study. This research included the critical success factors and lessons learnt from the systems employed by others. Experimental field work was carried out to allow the critical evaluation of the implementation in the case study. The experimental method utilised a combination of qualitative and quantitative methods for data collection. The primary research instrument was a questionnaire designed to examine the degree in which critical success factors and Operations Excellence requirements were present in the organisation. The implementation shortcomings were successfully identified through the experimental work undertaken. These shortcomings, together with the review of the available literature on Operations Excellence, allowed for the proposition of recommendations with the objective of successful utilisation of Operations Excellence programs for large enterprises. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014
2

A critical review of Operations Excellence programs : a petrochemical company as case study / Neeven Govindsamy

Govindsamy, Neeven January 2014 (has links)
Operations improvement methodologies have been adopted by manufacturing companies since the early 20th century. Japanese manufacturers were able to offer products of high quality and efficient production costs through systems such as Lean. Manufacturers in the West soon adopted systems of their own thereafter. Operations Excellence is a generic term used to describe such systems, and can be described as a management system delivering competitiveness through the continuous improvement of operational performance. This study provides a critical review of the implementation of an Operations Excellence program by examining the system adopted by a petrochemical company in South Africa. The review allowed the implementation shortcomings to be identified so that resolutions could be suggested, thus facilitating successful utilisation of the system. An evaluation of Operations Excellence programs utilised globally and at the case study organisation was carried out as part of a literature study. This research included the critical success factors and lessons learnt from the systems employed by others. Experimental field work was carried out to allow the critical evaluation of the implementation in the case study. The experimental method utilised a combination of qualitative and quantitative methods for data collection. The primary research instrument was a questionnaire designed to examine the degree in which critical success factors and Operations Excellence requirements were present in the organisation. The implementation shortcomings were successfully identified through the experimental work undertaken. These shortcomings, together with the review of the available literature on Operations Excellence, allowed for the proposition of recommendations with the objective of successful utilisation of Operations Excellence programs for large enterprises. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014
3

Critical evaluation of the theory of constraints lean six sigma continuous improvement management approach / Rojanette van Tonder.

Van Tonder, Rojanette January 2011 (has links)
Three methodologies are associated with production optimisation, namely, Theory of Constraints (TOC), Lean and Six Sigma – and each boasts with a number of success stories. This dissertation addresses the possibility of implementing all three these methodologies in a specific sequence at an organisation and also sets out to determine the impact of this implementation. A literature survey was conducted on all three stand-alone methodologies as well as on the combined methodology, which is called the Theory of Constrains Lean Six Sigma (TLS). TLS literature suggests that TOC should be implemented first with a view to identify the constraint in an organisation. Lean implementation should follow in order to eliminate any waste in the organisation. Lastly, Six Sigma should be implemented to optimise the process variability. TOC literature explains that The Goal of any organisation is to make money. All other objectives are only the means of achieving The Goal. The literature further indicates that the constraint in any organisation determines the drumbeat, and that this constraint should be managed by means of the Drum-Buffer-Rope methodology. Lean literature points towards 14 Management Principles by means of which an organisation should be managed in order to become a Lean organisation, while Six Sigma literature is concerned with the DMAIC (Define-Measure-Analyse-Improve-Control) methodology used for improvement projects and the belt system that is used to manage these improvement projects. Jonker Sailplanes, a sailplanes manufacturer in Potchefstroom, South Africa, was used as a case study for the implementation of TLS. A description is given of the processes and procedures that were followed before and after the implementation of TLS. The TLS methodology had to be adapted in order to meet the specific needs of Jonker Sailplanes into an adapted 14-step TLS implementation plan. After implementing TOC and Lean at Jonker Sailplanes, it was found that the organisation was not ready for the transition from Lean projects to Six Sigma projects. The implementation of Six Sigma was therefore referred for future research. One of the most significant findings of the current study was the very positive impact that the implementation of TLS had on the organisation: the production tempo (throughput) of the organisation has increased while the operating expenses per aircraft have decreased. This confirms that the profit per aircraft has increased. A critical evaluation of the implementation of the TLS methodology can therefore maintain that the implementation of TLS at Jonker Sailplanes was a success since the production tempo (throughput) and the organisational profit were increased and the implementation of the methodology was done with relative ease. In terms of interpreting results it was also necessary to set out how Jonker Sailplanes proceeded from a prototyping environment to a production setup, and how specifically identifying the constraint helped to achieve this transition. Furthermore, is it argued that when Lean is implemented before TOC, this could move the organisation away from The Goal, which is to make money. The interpretation of findings suggests that the procedure followed at Jonker Sailplanes was the most appropriate one. Finally, recommendations are made for future studies in terms of how to further improve the impact of the TLS implementation at Jonker Sailplanes. / Thesis (M.Ing. (Development and Management))--North-West University, Potchefstroom Campus, 2011.
4

Critical evaluation of the theory of constraints lean six sigma continuous improvement management approach / Rojanette van Tonder.

Van Tonder, Rojanette January 2011 (has links)
Three methodologies are associated with production optimisation, namely, Theory of Constraints (TOC), Lean and Six Sigma – and each boasts with a number of success stories. This dissertation addresses the possibility of implementing all three these methodologies in a specific sequence at an organisation and also sets out to determine the impact of this implementation. A literature survey was conducted on all three stand-alone methodologies as well as on the combined methodology, which is called the Theory of Constrains Lean Six Sigma (TLS). TLS literature suggests that TOC should be implemented first with a view to identify the constraint in an organisation. Lean implementation should follow in order to eliminate any waste in the organisation. Lastly, Six Sigma should be implemented to optimise the process variability. TOC literature explains that The Goal of any organisation is to make money. All other objectives are only the means of achieving The Goal. The literature further indicates that the constraint in any organisation determines the drumbeat, and that this constraint should be managed by means of the Drum-Buffer-Rope methodology. Lean literature points towards 14 Management Principles by means of which an organisation should be managed in order to become a Lean organisation, while Six Sigma literature is concerned with the DMAIC (Define-Measure-Analyse-Improve-Control) methodology used for improvement projects and the belt system that is used to manage these improvement projects. Jonker Sailplanes, a sailplanes manufacturer in Potchefstroom, South Africa, was used as a case study for the implementation of TLS. A description is given of the processes and procedures that were followed before and after the implementation of TLS. The TLS methodology had to be adapted in order to meet the specific needs of Jonker Sailplanes into an adapted 14-step TLS implementation plan. After implementing TOC and Lean at Jonker Sailplanes, it was found that the organisation was not ready for the transition from Lean projects to Six Sigma projects. The implementation of Six Sigma was therefore referred for future research. One of the most significant findings of the current study was the very positive impact that the implementation of TLS had on the organisation: the production tempo (throughput) of the organisation has increased while the operating expenses per aircraft have decreased. This confirms that the profit per aircraft has increased. A critical evaluation of the implementation of the TLS methodology can therefore maintain that the implementation of TLS at Jonker Sailplanes was a success since the production tempo (throughput) and the organisational profit were increased and the implementation of the methodology was done with relative ease. In terms of interpreting results it was also necessary to set out how Jonker Sailplanes proceeded from a prototyping environment to a production setup, and how specifically identifying the constraint helped to achieve this transition. Furthermore, is it argued that when Lean is implemented before TOC, this could move the organisation away from The Goal, which is to make money. The interpretation of findings suggests that the procedure followed at Jonker Sailplanes was the most appropriate one. Finally, recommendations are made for future studies in terms of how to further improve the impact of the TLS implementation at Jonker Sailplanes. / Thesis (M.Ing. (Development and Management))--North-West University, Potchefstroom Campus, 2011.
5

Quantification of carbon emissions and savings in smart grids

Eng Tseng, Lau January 2016 (has links)
In this research, carbon emissions and carbon savings in the smart grid are modelled and quantified. Carbon emissions are defined as the product of the activity (energy) and the corresponding carbon factor. The carbon savings are estimated as the difference between the conventional and improved energy usage multiplied by the corresponding carbon factor. An adaptive seasonal model based on the hyperbolic tangent function (HTF) is developed to define seasonal and daily trends of electricity demand and the resultant carbon emissions. A stochastic model describing profiles of energy usage and carbon emissions for groups of consumers is developed. The flexibility of the HTF for modelling cycles of energy consumption is demonstrated and discussed with several case studies. The analytical description to determine electricity grid carbon intensity in the UK is derived, using the available fuel mix data from the Elexon portal. The uncertain realisation of energy data is forecasted and assimilated using the ensemble Kalman filter (EnKF). The numerical optimisation of carbon emissions and savings in the smart grid is further performed using the ensemble-based Closed-loop Production Optimisation Scheme (EnOpt). The EnOpt involves the optimisation of fuel costs and carbon emissions (maximisation of carbon savings) in the smart grid subject to the operational control constraints. The software codes for the based on the application of EnKF and EnOpt are developed, and the optimisation of energy, cost and emissions is performed. The numerical simulation shows the ability of EnKF in forecasting and assimilating the energy data, and the robustness of the EnOpt in optimising costs and carbon savings. The proposed approach addresses the complexity and diversity of the power grid and may be implemented at the level of the transmission operator in collaboration with the operational wholesale electricity market and distribution network operators. The final stage of work includes the quantification of carbon emissions and savings in demand response (DR) programmes. DR programmes such as Short Term Operating Reserve (STOR), Triad, Fast Reserve, Frequency Control by Demand Management (FCDM) and smart meter roll-out are included, with various types of smart interventions. The DR programmes are modelled with appropriate configurations and assumptions in power plants used in the energy industry. This enables the comparison of emissions between the business-as-usual (BAU) and the smart solutions applied, thus deriving the carbon savings. Several case studies involving the modelling and analysing DR programmes are successfully performed. Thus, the thesis represents novel analytical and numerical techniques applied in the fast-growing UK market of smart energy solutions.
6

Modely cílového programování: teorie, aplikace, softwarová podpora / Goal Programming Models: Theory, Applications, Software Support

Skočdopolová, Veronika January 2014 (has links)
Goal programming is an approach for solving decision problems. The aim of this doctoral thesis is to show the practical use of this approach for solving real problems. The first chapter brings a brief introduction to multicriteria decision making. The second chapter is devoted to goal programming, its history, theory, criticism and also to its practical applications. The third chapter deals with description of a model for optimisation of white mass production. This model utilises the goal programming principle to deal with measuring deviations of raw materials' composition. A part of this chapter is a presentation of OPTIPROT, an application that implements the mentioned model. In the fourth chapter there are described three mathematical models for timetabling at a department level; two multistage models and one complex model. All three models are formulated utilising goal programming. In this chapter there is also described an application that implements the complex model for timetabling.
7

Production, in vitro modification, and interaction analysis of a hydroxyproline-dependent protein

Plavsic, Milica January 2023 (has links)
The development of a biologic protein involves different stages and becomes a highly complex process which can be costly and time consuming to scale up for industrial production. Therefore, optimization is a necessary part of the production process development to lower the production expenses.An on-going project is working on upscaling the production of a protein derived from mussel adhesive proteins (MAPs) which has great properties to be used as a pharmaceutical drug or in medical devices. The protein is expressed in a bacterial host cell and the necessary post translational modifications (PTMs) are done in-vitro using enzymes. The work presented in this report was done to optimize both the protein production in lab scale bioreactors and the enzymatic reaction using an immobilized prolyl-4-hydroxylase (P4H) which does a post translational modification on prolyl-residues. Additionally, an interaction study was conducted to better understand the hydroxylation using the prolyl-4-hydroxylase.For the bioreactor optimization four initial trials were performed testing different growth and induction temperatures and also comparing exponential to linear feeding. From these trials it appeared that having 30 ℃ growth overnight and induction at the same temperature in combination with an exponential feeding rate gave the best results. The modifications done by the prolyl-4-hydroxylase were analysed by LC-MS and suggest that longer incubation time and more immobilized protein gives more modifications in the tested ranges and the possibilities of reusing the immobilized proteins looks promising. No conclusive data was discovered for the optimal substrate concentration. The interaction study revealed the importance of reagents used for catalysis with the enzyme to be present for interaction to occur, however more work needs to be done to discover an accurate KD for the interaction.

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