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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.
71

Evolución de galaxias en cúmulos revelada a través de la relación color magnitud

Jiménez, Noelia 27 March 2014 (has links)
En este Trabajo de Tesis se investigan los procesos involucrados en el desarrollo de la Relación Color Magnitud (RCM) de galaxias en cúmulos. Esta relación comprende galaxias de tipo temprano y corresponde a la secuencia roja (SR) observada en el plano color magnitud. La distribución de galaxias en este plano es bimodal en los colores y parte de las galaxias se distribuyen en una zona difusa llamada “nube azul”. La SR está formada mayormente por galaxias pobres en gas con baja formación estelar, prototípicamente galaxias de tipo temprano. Estas galaxias constituyen el objeto de estudio de la presente investigación y la relación color magnitud que las caracteriza será referida como RCM.
72

Hydrological Modeling for Climate Change Impact Assessment : Transferring Large-Scale Information from Global Climate Models to the Catchment Scale

Teutschbein, Claudia January 2013 (has links)
A changing climate can severely perturb regional hydrology and thereby affect human societies and life in general. To assess and simulate such potential hydrological climate change impacts, hydrological models require reliable meteorological variables for current and future climate conditions. Global climate models (GCMs) provide such information, but their spatial scale is too coarse for regional impact studies. Thus, GCM output needs to be downscaled to a finer scale either through statistical downscaling or through dynamic regional climate models (RCMs). However, even downscaled meteorological variables are often considerably biased and therefore not directly suitable for hydrological impact modeling. This doctoral thesis discusses biases and other challenges related to incorporating climate model output into hydrological studies and evaluates possible strategies to address them. An analysis of possible sources of uncertainty stressed the need for full ensembles approaches, which should become standard practice to obtain robust and meaningful hydrological projections under changing climate conditions. Furthermore, it was shown that substantial biases in current RCM simulations exist and that correcting them is an essential prerequisite for any subsequent impact simulation. Bias correction algorithms considerably improved RCM output and subsequent streamflow simulations under current conditions. In addition, differential split-sample testing was highlighted as a powerful tool for evaluating the transferability of bias correction algorithms to changed conditions. Finally, meaningful projections of future streamflow regimes could be realized by combining a full ensemble approach with bias correction of RCM output: Current flow regimes in Sweden with a snowmelt-driven spring flood in April will likely change to rather damped flow regimes that are dominated by large winter streamflows.
73

A maintenance strategy for a network of automated fluid management systems / by Francois Oosthuizen.

Oosthuizen, Francois January 2012 (has links)
The current economic climate in South Africa requires organisations to optimise available resources – human and otherwise – to successfully sustain business operations. This is especially true for the growing SMME sector in South Africa. Organisations utilising hydrocarbon based products for input products into their respective process - specifically fuels and lubricants – face an even greater challenge in optimising resource usage as fuel and lubricant prices have increased substantially over the last decade. Automated and advanced technological solutions to properly and effectively manage these fuel and lubricant resources must be employed within organisations. This is critical as fuel and lubricants can constitute a large part of the annual expenditure within an organisation. Such organisations can include: • Mining operations • Transport operations • Agricultural operations • Maritime operations Newcom Fluid Management has developed a Fuel & Fluid Management Solution which consists of an electronic control system and various other elements to assist organisations in managing these fuel and lubricant resources. The Newcom FMS makes use of physical hardware on the client’s site as well as an internet based software system to control, monitor and report on all fuel and lubricant usages. There is also a large human resource element behind the system which continuously maintains these remote systems such that clients can enjoy the availability of fuels and lubricants when desired. The Newcom FMS must be properly maintained and resources optimised to allow Newcom to not only make a profit, but to stay competitive in the market place by providing clients with a sustainable and available solution. Therefore a properly researched maintenance management strategy must be developed for Newcom and the Newcom FMS solution to ensure that not only the client’s resources are optimised, but also Newcom’s resources in order to maintain the Newcom FMS. The aim of this research was to: • Research the theory behind maintenance management; • Identify and develop a sustainable maintenance strategy for the Newcom FMS solution taking into account the success factors as required by Newcom; • Test the experimental strategy and the current maintenance program at current Newcom clients and capture data on the two strategies employed; • Analyse and compare the experimental data to determine the effectiveness of the experimental maintenance strategy versus the corrective strategy; • Provide the experimental maintenance strategy “product” to Newcom along with the data obtained in the experiment as well as the recommendations on the way forward with the data obtained from the experiment serving as inputs. The parameters which were measured in the experiment were: • System availability; • Strategy expenditure and • Resources usage. The parameters were selected by Newcom as being the most pertinent to their current operational environment. Achieving success in these areas would effectively increase the probability of a successful maintenance management strategy for Newcom. • The experimental data was captured for the period the experiment was executed for. This data was analysed, the results were interpreted a / Thesis (MIng (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2013.
74

A maintenance strategy for a network of automated fluid management systems / by Francois Oosthuizen.

Oosthuizen, Francois January 2012 (has links)
The current economic climate in South Africa requires organisations to optimise available resources – human and otherwise – to successfully sustain business operations. This is especially true for the growing SMME sector in South Africa. Organisations utilising hydrocarbon based products for input products into their respective process - specifically fuels and lubricants – face an even greater challenge in optimising resource usage as fuel and lubricant prices have increased substantially over the last decade. Automated and advanced technological solutions to properly and effectively manage these fuel and lubricant resources must be employed within organisations. This is critical as fuel and lubricants can constitute a large part of the annual expenditure within an organisation. Such organisations can include: • Mining operations • Transport operations • Agricultural operations • Maritime operations Newcom Fluid Management has developed a Fuel & Fluid Management Solution which consists of an electronic control system and various other elements to assist organisations in managing these fuel and lubricant resources. The Newcom FMS makes use of physical hardware on the client’s site as well as an internet based software system to control, monitor and report on all fuel and lubricant usages. There is also a large human resource element behind the system which continuously maintains these remote systems such that clients can enjoy the availability of fuels and lubricants when desired. The Newcom FMS must be properly maintained and resources optimised to allow Newcom to not only make a profit, but to stay competitive in the market place by providing clients with a sustainable and available solution. Therefore a properly researched maintenance management strategy must be developed for Newcom and the Newcom FMS solution to ensure that not only the client’s resources are optimised, but also Newcom’s resources in order to maintain the Newcom FMS. The aim of this research was to: • Research the theory behind maintenance management; • Identify and develop a sustainable maintenance strategy for the Newcom FMS solution taking into account the success factors as required by Newcom; • Test the experimental strategy and the current maintenance program at current Newcom clients and capture data on the two strategies employed; • Analyse and compare the experimental data to determine the effectiveness of the experimental maintenance strategy versus the corrective strategy; • Provide the experimental maintenance strategy “product” to Newcom along with the data obtained in the experiment as well as the recommendations on the way forward with the data obtained from the experiment serving as inputs. The parameters which were measured in the experiment were: • System availability; • Strategy expenditure and • Resources usage. The parameters were selected by Newcom as being the most pertinent to their current operational environment. Achieving success in these areas would effectively increase the probability of a successful maintenance management strategy for Newcom. • The experimental data was captured for the period the experiment was executed for. This data was analysed, the results were interpreted a / Thesis (MIng (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2013.
75

Metodologies d’anulació en substrats heterocíclics: Reaccions de RCM i ciclacions de Heck

Alonso Serrano, Sandra 12 February 2010 (has links)
La present Tesi Doctoral es situa en el context de l’estudi d’estratègies sintètiques per a la formació d’anells en l’àrea heterocíclica. En particular, s’han avaluat les possibilitats sintètiques de la combinació de dues reaccions d’eficàcia prou reconeguda per a la formació d’enllaços carboni-carboni, la reacció de RCM i la reacció intramolecular de Heck d’halurs vinílics, per a la construcció de les estructures policíliques amb pont característiques dels alcaloides ervitsina i aparicina, així com també de la unitat superior de la vinorelbina. Els principals aconseguiments del treball i les conclusions més significatives que se’n deriven s’exposen a continuació: • La reacció de RCM de diens indòlics ha mostrat ser un bon procediment per a la formació d’anells de 8 baules fusionats amb el nucli indòlic. L’eficiència de la ciclació, combinada amb la facilitat de preparació dels substrats diènics a partir de compostos indòlics senzills, determina que l’estratègia pugui ser emprada com a via d’accés a les subestructures tricícliques tant de l’alcaloide aparicina com de la unitat superior de la vinorelbina. • L’aminació reductora d’indole-3-carbaldehids amb alquenilamines permet instal•lar cadenes d’alquenilaminometil a la posició 3 de l’heterocicle, d’interès per la preparació dels substrats diènics precursors de diversos azacicles per RCM. En el cas particular de 2-vinil-3-indolecarbaldehids, el procés d’aminació reductora no és compatible amb la presència d’un grup fenilsulfonil a l’àtom de nitrogen indòlic, ja que en comptes d’obtenir-se la corresponent amina secundària, s’observa la formació ràpida del nucli de tetrahidro-γ-carbolina. L’anulació és el resultat de l’addició conjugada de l’amina primària a l’agrupació d’aldehid γ, δ insaturat del substrat, seguida d’un procés d’aminació reductora intramolecular. • La metodologia de doble anulació RCM-Heck possibilita l’accés al sistema amb pont de 2-azabiciclo[4.3.1]decà característic de l’alcaloide ervitsina. En concret, la reacció de RCM quimioselectiva d’un triè indòlic genera un ciclohepta[b]indole, amb un doble enllaç adequat per al tancament subsegüent de l’anell de piperidina mitjançant un acoblament intramolecular de Heck amb l’halur vinílic, connectat al sistema anular a través de l’àtom de nitrogen. Si bé s’ha accedit al sistema tetracíclic de l’alcaloide que incorpora el substituent E-etilidè a la posició 20, l’estratègia no s’ha pogut estendre a la preparació de compostos tetracíclics funcionalitzats a la posició 3. • S’ha dut a terme la primera síntesi total de l’alcaloide aparicina mitjançant una via sintètica concisa que implica com a etapas clau: (i) la reacció de RCM d’un diè indòlic per construir l’anell central de 8 baules; (ii) la isomerització promoguda per base del doble enllaç resultant de la ciclació, amb desprotecció concomitant de l’àtom de nitrogen indòlic; i (iii) la ciclació de Heck d’un halur vinílic per completar la formació de l’esquelet amb pont d’1-azabiciclo[4.2.2]decà i al mateix temps introduïr els dos dobles enllaços exocíclics de l’alcaloide. • La inserció de l’agrupació de 2-etilpropè entre l’àtom de nitrogen alifàtic i la posició 4 d’un azocino[4,3-b]indole mitjançant una seqüència d’N-alquilació seguida de ciclació de Heck permet la formació del sistema amb pont d’1-azabiciclo[5.3.1]undecà característic de la unitat superior de la vinorelbina. Aquest resultat, juntament amb l’obtingut en el context de la síntesi de l’aparicina, posa de manifest la validesa dels acoblaments intramoleculars de Heck en els quals intervenen dobles enllaços inclosos en anells mitjans. / The first part of this thesis work focus attention to: • The new synthetic route to the azocino[4,3-b]indole system relying on RCM of 2-allyl-3-(allyl-aminomethyl)indoles. The efficiency of the cyclization combined with the easy preparation of the dienic precursors from simple indolic derivates make this strategy attractive for the construccion of medium-sized indolo 2,3-fused carbo- and azacycles, which are scaffolds found in many bioactive compounds. • Our efforts in getting more azepinoindole systems leads to tetrahydro γ-carbolines. The reaction of N-(phenilsulfonyl)-2-vynil-3-indolecarbaldehydes with primary amines under mild reductive amination conditions leads to tetrahydro-γ-carbolines. The process can be suppressed by changing the protecting group at the indole nitrogen for a methoxymethil group, thus allowing the preparation of RCM substrates for azepinoindole synthesis. In the second part: • An efficient approach to the bridged framework of the indole alkaloid ervitsine have been done. The RCM reaction from a 2,3-disubstituted indole followed by a vynil halide Heck cyclazation upon the resulting cycloheptene ring gives short access to the Ervitsine alkaloid skeleton. • The first total synthesis of (±)-apparicine has been accomplished by a concise route employing a vynil halide Heck cyclization to close the bridged piperidine ring in the last synthetic step. • An efficient approach to the high subunit of Vinorelbin has been done. The subunit has been successfully assembled developing an indole-templated RMC followed by an intramolecular Heck cyclization.
76

Análise comparativa de métodos de recuperação de emissividade com dados do infravermelho termal do sensor Aster

Becerra Rondón, Adriana Coromoto January 2017 (has links)
A emissividade da superfície terrestre (EST) é uma propriedade importante na caracterização de alvos através do Sensoriamento Remoto (SR). A estimativa da EST envolve a aplicação de uma função indeterminada de várias variáveis em dados de radiância contaminados por uma atmosfera de complexa modelagem. Dunas, em geral, são compostas por quartzo, cujo comportamento emissivo é bem caracterizado com sensores que operam entre 8–12μm. Neste trabalho foram avaliados 4 métodos de recuperação de temperatura-emissividade a partir de dados de radiância corrigida dos efeitos atmosféricos. Os quatro métodos foram aplicados em dados do subsistema do infravermelho termal (TIR) do sensor ASTER e são: Método da Emissividade Normalizada (MEN), Método da Banda de Referência (MBR), Separação de Emissividade e Temperatura (TES) e Resíduos Alpha (α-Residual). Foram geradas imagens de emissividade, cujas amostras puras (controle) de quartzo foram comparadas com uma curva homóloga da biblioteca espectral do Laboratório de Sensoriamento Remoto do Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia da Universidade Federal do Rio Grande do Sul (UFRGS). Neste trabalho, os métodos foram comparados pelas diferenças na emissividade média, temperatura média de uma imagem ASTER e geometria da curva através de seus valores alphas. Obteve-se como resultado que o método TES apresentou uma emissividade média absoluta maior em relação ao MEN e MBR. A temperatura média para métodos MEN e MBR foi de 35,18ºC, TES de 30,10ºC e o α-Residual não gerou um valor de temperatura, pois não considera esta variável na estimativa do espectro alpha. A geometria da curva do método TES foi a mais próxima da curva espectral de referência. Os métodos comparados neste trabalho não obtiveram um desempenho quantitativo dentro dos limiares certos, é dizer no intervalo de emissividade de um quartzo a 29ºC. Os métodos neste trabalho tiveram uma tendência a superestimar os valores de temperatura e consequentemente os valores de emissividade, devido a uma correção atmosférica inexata em condições de alta umidade, suposições iniciais (emissividade) com grande erro, heterogeneidade do alvo. Em contrapartida se obteve bom desempenho na individualização dos campos de dunas preservando a forma da curva espectral (geometria) do quartzo. / The land surface emissivity (LSE) is an important property in the characterization of targets through Remote Sensing (RS). The estimation of LSE involves the application of an indeterminate function of several variables in radiance data contaminated by an atmosphere of complex modeling. In general, sand dunes are composed of quartz, whose spectral behavior is well characterized with sensors operating between 8-12μm. In this work, four methods of temperature-emissivity recovery were evaluated from atmospheric effects corrected radiance data. The four methods were applied to data from the thermal infrared (TIR) subsystem of the ASTER sensor, and they are: Normalization Emissivity Method (NEM), Reference Channel Method (RCM), Temperature Emissivity Separation (TES) and Alpha Residuals Method (α- Residual). Emissivity images were generated, whose pure quartz samples (control) were compared to a homologous curve of the spectral library of the Remote Sensing Laboratory of the State Center for Remote Sensing and Meteorology Research at the Federal University of Rio Grande do Sul (UFRGS). In this study, the methods were compared by differences in mean emissivity, mean temperature of ASTER image and curve geometry through their alpha values. As a result, the TES method presented a higher mean absolute emissivity, in relation to NEM and RCM. The mean temperature for NEM and RCM methods was 35.18 °C, TES was 30.10 °C and α-Residuals did not generate a temperature value, since it does not consider this variable in the estimation of the alpha spectrum. The geometry of the TES method curve was the closest to the reference spectral curve. The methods compared in this work did not obtain a quantitative performance within the certain thresholds, in the emissivity range of a quartz at 29 °C. The methods tend to overestimate the temperature values and consequently the emissivity values due to an inaccurate atmospheric correction under conditions of high humidity, initial assumptions (emissivity) with great error, heterogeneity of the target. In contrast, a good performance was obtained in the individualization of the dune fields, preserving the shape of the spectral curve (geometry) of the quartz.
77

Análise comparativa de métodos de recuperação de emissividade com dados do infravermelho termal do sensor Aster

Becerra Rondón, Adriana Coromoto January 2017 (has links)
A emissividade da superfície terrestre (EST) é uma propriedade importante na caracterização de alvos através do Sensoriamento Remoto (SR). A estimativa da EST envolve a aplicação de uma função indeterminada de várias variáveis em dados de radiância contaminados por uma atmosfera de complexa modelagem. Dunas, em geral, são compostas por quartzo, cujo comportamento emissivo é bem caracterizado com sensores que operam entre 8–12μm. Neste trabalho foram avaliados 4 métodos de recuperação de temperatura-emissividade a partir de dados de radiância corrigida dos efeitos atmosféricos. Os quatro métodos foram aplicados em dados do subsistema do infravermelho termal (TIR) do sensor ASTER e são: Método da Emissividade Normalizada (MEN), Método da Banda de Referência (MBR), Separação de Emissividade e Temperatura (TES) e Resíduos Alpha (α-Residual). Foram geradas imagens de emissividade, cujas amostras puras (controle) de quartzo foram comparadas com uma curva homóloga da biblioteca espectral do Laboratório de Sensoriamento Remoto do Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia da Universidade Federal do Rio Grande do Sul (UFRGS). Neste trabalho, os métodos foram comparados pelas diferenças na emissividade média, temperatura média de uma imagem ASTER e geometria da curva através de seus valores alphas. Obteve-se como resultado que o método TES apresentou uma emissividade média absoluta maior em relação ao MEN e MBR. A temperatura média para métodos MEN e MBR foi de 35,18ºC, TES de 30,10ºC e o α-Residual não gerou um valor de temperatura, pois não considera esta variável na estimativa do espectro alpha. A geometria da curva do método TES foi a mais próxima da curva espectral de referência. Os métodos comparados neste trabalho não obtiveram um desempenho quantitativo dentro dos limiares certos, é dizer no intervalo de emissividade de um quartzo a 29ºC. Os métodos neste trabalho tiveram uma tendência a superestimar os valores de temperatura e consequentemente os valores de emissividade, devido a uma correção atmosférica inexata em condições de alta umidade, suposições iniciais (emissividade) com grande erro, heterogeneidade do alvo. Em contrapartida se obteve bom desempenho na individualização dos campos de dunas preservando a forma da curva espectral (geometria) do quartzo. / The land surface emissivity (LSE) is an important property in the characterization of targets through Remote Sensing (RS). The estimation of LSE involves the application of an indeterminate function of several variables in radiance data contaminated by an atmosphere of complex modeling. In general, sand dunes are composed of quartz, whose spectral behavior is well characterized with sensors operating between 8-12μm. In this work, four methods of temperature-emissivity recovery were evaluated from atmospheric effects corrected radiance data. The four methods were applied to data from the thermal infrared (TIR) subsystem of the ASTER sensor, and they are: Normalization Emissivity Method (NEM), Reference Channel Method (RCM), Temperature Emissivity Separation (TES) and Alpha Residuals Method (α- Residual). Emissivity images were generated, whose pure quartz samples (control) were compared to a homologous curve of the spectral library of the Remote Sensing Laboratory of the State Center for Remote Sensing and Meteorology Research at the Federal University of Rio Grande do Sul (UFRGS). In this study, the methods were compared by differences in mean emissivity, mean temperature of ASTER image and curve geometry through their alpha values. As a result, the TES method presented a higher mean absolute emissivity, in relation to NEM and RCM. The mean temperature for NEM and RCM methods was 35.18 °C, TES was 30.10 °C and α-Residuals did not generate a temperature value, since it does not consider this variable in the estimation of the alpha spectrum. The geometry of the TES method curve was the closest to the reference spectral curve. The methods compared in this work did not obtain a quantitative performance within the certain thresholds, in the emissivity range of a quartz at 29 °C. The methods tend to overestimate the temperature values and consequently the emissivity values due to an inaccurate atmospheric correction under conditions of high humidity, initial assumptions (emissivity) with great error, heterogeneity of the target. In contrast, a good performance was obtained in the individualization of the dune fields, preserving the shape of the spectral curve (geometry) of the quartz.
78

Design and Development of a Maintenance Knowledge-Base System Based on Common KADS Methodology

Arab Maki, Alireza, Shariat Zadeh, Navid January 2010 (has links)
The objective of this thesis is to design and develop a knowledge base model to support the maintenance system structure. The aim of this model is to identify the failure modes which are the heart of maintenance system through the functional analysis and then serves as adecision support system to define the maintenance tasks and finally to implement a preventive maintenance task. This knowledge base management system is suitable to design and develop maintenance system since it encompasses all necessary steps in maintenance area. Moreover, it is capable of being integrated with other knowledge base systems. The structure and the environment of this knowledge base system is flexible to allow users to deploy different kinds of tools which they will. It is also a well structured approach to develop, debug, upgrade and trace. In this thesis, the CommonKADS methodology is used as the knowledge base methodology. At the first step, a knowledge base system is developed to create the maintenance system infrastructure. To implement this, Reliability-Centered Maintenance (RCM) has been chosen as the method to design a maintenance system. In order to make it more specified, a Spindlesubsystem is taken as a case study to make the model clearer. Secondly, another knowledge base system is developed for decision making process to select the suitable maintenance task and finally, a general knowledge base model is developed for condition-based monitoring onSpindle. In chapter 1, background, previous works and gap analysis have been surveyed. Then in chapter 2 the methodology and tools have been discussed and described. Design and development the knowledge base for maintenance system is described in detail in chapter 3 and finally in chapter 4, the conclusion and the future works are presented.
79

Gestión de mantenimiento centrado en la confiabilidad de estación de bombeo N°1 de la planta de tratamiento de agua potable N°1 de Chiclayo en la empresa Epsel S.A. para el aumento de la producción en el servicio de agua potable en la ciudad de Chiclayo

Sarmiento Melendez, Luis Angel January 2017 (has links)
La presente investigación está centrada en hacer una gestión de mantenimiento centrado en la confiabilidad de la estación de bombeo N°1 de la planta de tratamiento N°1 de agua potable de Chiclayo en la Empresa EPSEL S.A., dicha empresa brinda el servicio de agua potable y alcantarillado a toda la región y con el fin de lograr un aumento de la producción en el servicio de agua potable en la ciudad de Chiclayo se decidió por el desarrollo de esta gestión. En primer lugar se procedió a realizar un diagnóstico situacional de la estación de bombeo con el fin de identificar los principales problemas que acarrean a este sistema. Dicha estación cuenta con un número elevado de averías lo que ocasionan detención en la producción y distribución. Posteriormente se definió las teorías y normativas que permitieron el desarrollo correcto de la aplicación de este mantenimiento, como lo son el análisis de criticidad, diagrama causa efecto, análisis de modo y de falla y distribución de Weibull entre otros; para luego, definir el plan de gestión a aplicar basado en el mantenimiento centrado en la confiabilidad, y en última instancia se realizó un análisis costo-beneficio de la propuesta que nos permitirá conocer la viabilidad del proyecto. A través del cumplimiento de los objetivos propuestos se logrará obtener la confiabilidad de los equipos pertenecientes a dicha estación de bombeo, incluyendo las herramientas y métodos utilizados para el establecimiento de la gestión de mantenimiento de la misma, consiguiendo a través de estos mejorar la producción de agua potable y la generación de ahorro.
80

Generator maintenance scheduling models in power systems : integrated cost models for generator maintenance strategy under market environment

Al-Arfaj, Khalid Abdulaziz January 2009 (has links)
Change from a regulated to deregulated structure means that, the centralized maintenance system is not valid any more. In the surveyed published literature, there is not a single model which incorporates all maintenance cost components to analyze the effect of different maintenance strategies for generator companies (GENCOs). The work enclosed in this thesis demonstrates that there is a considerable requirement for accurately modelling cost components of the maintenance model, to be used in maintenance scheduling for deregulated power system, in order to attain a superior schedule with major financial and operational impact. This research investigates and models most cost factors that affect the maintenance activities of the deregulated GENCOs, and demonstrates the utilization of the developed cost models in maintenance scheduling. It also presents the data gathering process for the developed maintenance cost model. A generator maintenance scheduling model that considers direct and indirect maintenance costs, opportunity costs (i.e. loss of customer goodwill), effective maintenance strategies, failures, and interruptions is developed. A Genetic Algorithm (GA) based approach is employed to achieve maintenance schedules to various generators maintenance scenarios. An Analytical Hierarchy Process (AHP) approach is proposed for modelling customer goodwill. The maintenance model was redeveloped under the Reliability Centred Maintenance (RCM) strategy to analyze the effect of a maintenance strategy on maintenance costs. Case studies are presented to demonstrate the utilisation of the developed models.The investigation shows that the market prices, opportunity costs and maintenance strategy have an effect on the final maintenance schedule. The research demonstrates that the cost components are critical factors to achieve an effective maintenance schedule, and they must be considered and carefully modelled in order to reflect more realistic situation for maintenance scheduling of generator units in deregulation environment.

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