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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

Estimating marginal costs for the Austrian railway system

Munduch, Gerhard, Pfister, Alexander, Sögner, Leopold, Stiassny, Alfred January 2002 (has links) (PDF)
This article presents an econometric analysis of the maintenance costs for the Austrian railway system. The data contain observations of track maintenance costs from 1998 to 2000. Our analysis identifies the cost driving factors in order to determine estimates of marginal costs, as required by the infrastructure provision principles of the European Union. The analysis identifies the variables "track length" and "transported gross-tons" as the principal cost determinants. Furthermore, we observe that total costs as well as marginal costs increase with (i) a high proportion of the track occupied by train stations, (ii) the number of switches within a track, (iii) narrow bends, and (iv) considerable slopes. Moreover average as well as marginal costs for secondary lines are significantly higher than for main lines. (author's abstract) / Series: Department of Economics Working Paper Series
2

Gone with the Wind : The economic impact of disruptions A study of service and maintenance in the Swedish wind power market

Duncker, Nadja, Klötzer, Anneke, Larsson, Kristofer January 2010 (has links)
The purpose of this thesis is to explore disruptions Swedish wind turbines onshore are exposed to, and to estimate their economic impacts on the operators. We want to investigate whether there is a need for a more developed service and maintenance market within the Swedish wind power market. This study focuses on wind power, a renewable energy source in an emerging market, which experiences exponential growth. Sweden is a minor actor in the wind power market with a production of around 2 TWh yearly. The government aims at a total production of 10TWh in 2015 and 20TWh in 2020, which equals an annual growth of 24%. However, we hypothesize that the Swedish wind power market is negatively affected by a service and maintenance market which is underdeveloped due to a lack of competition. This results in lengthy repair times and disproportionate costs for wind power operators. The study was carried out by conducting semi-structured qualitative interviews and by sending out a survey to approximately 300 wind power operators. Six interviewees were wind power operators and one interviewee was a representative from an independent service supplier. We have also analysed the current cost situation of operators with theories about maintenance costs and we have also carried out an industry analysis on the service and maintenance market, which was based on Porter’s structural industry analysis. After conducting a structural analysis of the service and maintenance market, we can conclude a lack of competition today as there is a dominance of the wind turbine manufacturers as the service supplier. Furthermore we can see that this lack of competition has negative effects on the efficiency of the service and maintenance provided. The results also stress a need for a more developed service and maintenance market. We have found that the profitability for the Swedish wind power operators is challenged if the service and maintenance market is not keeping pace and meeting the demands of the rapidly growing Swedish wind power market as a whole.
3

Gone with the Wind : The economic impact of disruptions A study of service and maintenance in the Swedish wind power market

Duncker, Nadja, Klötzer, Anneke, Larsson, Kristofer January 2010 (has links)
<p>The purpose of this thesis is to explore disruptions Swedish wind turbines onshore are exposed to, and to estimate their economic impacts on the operators. We want to investigate whether there is a need for a more developed service and maintenance market within the Swedish wind power market.</p><p>This study focuses on wind power, a renewable energy source in an emerging market, which experiences exponential growth. Sweden is a minor actor in the wind power market with a production of around 2 TWh yearly. The government aims at a total production of 10TWh in 2015 and 20TWh in 2020, which equals an annual growth of 24%. However, we hypothesize that the Swedish wind power market is negatively affected by a service and maintenance market which is underdeveloped due to a lack of competition. This results in lengthy repair times and disproportionate costs for wind power operators.</p><p>The study was carried out by conducting semi-structured qualitative interviews and by sending out a survey to approximately 300 wind power operators. Six interviewees were wind power operators and one interviewee was a representative from an independent service supplier. We have also analysed the current cost situation of operators with theories about maintenance costs and we have also carried out an industry analysis on the service and maintenance market, which was based on Porter’s structural industry analysis.</p><p>After conducting a structural analysis of the service and maintenance market, we can conclude a lack of competition today as there is a dominance of the wind turbine manufacturers as the service supplier. Furthermore we can see that this lack of competition has negative effects on the efficiency of the service and maintenance provided. The results also stress a need for a more developed service and maintenance market. We have found that the profitability for the Swedish wind power operators is challenged if the service and maintenance market is not keeping pace and meeting the demands of the rapidly growing Swedish wind power market as a whole.</p>
4

Automatizovani dijagnostički modeli i njihov uticaj na pouzdanost tehničkih sistema / Automated diagnostic models and their influence on the reliability of technical systems

Ilić Božo 06 April 2016 (has links)
<p>Osnovni cilj ove doktorske disertacije bio je da se razvije novi automatizovani dijagnostiĉki model. Zatim da se praktiĉnom primenom tog modela (na konkretnom primeru automatizovane dijagnostike vitalnih komponenti tehniĉkih sistema u realnim pogonskim uslovima razliĉitih grana industrije) tehno-ekonomskom analizom potvrdi glavna hipoteza disertacije: &bdquo;Automatizovana dijagnostika tehniĉkih sistema u industriji (bazirana na kori&scaron;ćenju raĉunara i drugih savremenih informaciono-komunikacionih tehnologija) doprinosi porastu nivoau pouzdanosti i raspoloţivosti tih sistema, kao smanjenju ukupnih tro&scaron;kova i ekonomiĉnijem poslovanju preduzeća―.</p> / <p>The main objective of this doctoral thesis was to develop a new automated diagnostic model. Then with the practical usage of this model (in particular case of automated diagnostics vital components of technical systems in real operating conditions of different industries) with techno-economic analysis to confirm the main hypothesis of the dissertation: ―Automated diagnostics of technical systems in the industry (based on the use of computers and other modern information and communication technologies) contributes to the increase levels of reliability and availability of these systems, as well as the reduction of total costs and more economical management of the company‖.</p>
5

Genome scale metabolic models of plant tissues

Cheung, Chun Yue Maurice January 2013 (has links)
The aim of this thesis was to explore the use of genome-scale metabolic models to predict metabolic fluxes in plant tissues. Results from this thesis showed that the application of constraint-based modelling, namely flux balance analysis, to an Arabidopsis genome-scale metabolic model gave accurate predictions of metabolic fluxes in heterotrophic cell culture and in photosynthetic leaves. Two major factors important for the accuracy of model predictions were highlighted from the study: 1) the inclusion of energetic costs for transports and cellular maintenance in terms of ATP and NADPH; 2) consideration of the interactions between light and dark metabolism in modelling photosynthetic leaves. This study began with the construction of a well-curated and compartmented genome-scale metabolic model of Arabidopsis. Using the model, cellular maintenance costs in a heterotrophic cell culture under control and two stress conditions were estimated in terms of ATP and reductant usage. The results suggested that the cells were not stressed under hyperosmotic conditions. Comparisons between model predictions and experimentally estimated flux maps showed that the inclusion of transport and maintenance costs was important for obtaining accurate model flux predictions. To model leaf metabolism over a day-night cycle, a diel modelling framework was developed which took into account the interactions between light and dark metabolism. Numerous known features of metabolism in a C<sub>3</sub> leaf were predicted such as the nocturnal accumulation of citrate utilised for diurnal glutamate and glutamine synthesis and the operation of an incomplete TCA cycle during the day. Using the Arabidopsis genome-scale metabolic model and the diel modelling framework, the operation of the CAM cycle was predicted as a direct consequence of blocking the CO<sub>2</sub> exchange with the external air during the day to simulate closure of the stomata. Comparisons between model predictions of C<sub>3</sub> and various subtypes of CAM leaves suggested that photon and nitrogen use efficiencies are unlikely to be the driving forces for the evolution of CAM plants under the current atmospheric CO<sub>2</sub> concentration. Finally, the model was utilised to predict the changes in metabolic fluxes, in particular fluxes through various routes of alternative electron flow, in a C<sub>3</sub> leaf with varying light intensity, nitrogen availability and at different stages of leaf development. From the model flux predictions, it was shown that constraint-based modelling can be utilised to elucidate the distinct metabolic roles of enzymes in different subcellular compartments and the tissue-specific use of distinct forms of enzymes with different coenzyme specificities.
6

Application of the Analytic Hierarchy Process Optimization Algorithm in Best Management Practice Selection

Young, Kevin D. 29 September 2006 (has links)
The efficiency of a best management practice (BMP) is defined simply as a measure of how well the practice or series of practices removes targeted pollutants. While this concept is relatively simple, mathematical attempts to quantify BMP efficiency are numerous and complex. Intuitively, the pollutant removal capability of a BMP should be fundamental to the BMP selection process. However, as evidenced by the absence of removal efficiency as an influential criterion in many BMP selection procedures, it is typically not at the forefront of the BMP selection and design process. Additionally, of particular interest to any developer or municipal agency is the financial impact of implementing a BMP. Not only does the implementation cost exist, but there are long-term maintenance costs associated with almost any BMP. Much like pollutant removal efficiency, implementation and maintenance costs seem as though they should be integral considerations in the BMP selection process. However, selection flow charts and matrices employed by many localities neglect these considerations. Among the categories of criteria to consider in selecting a BMP for a particular site or objective are site-specific characteristics; local, state, and federal ordinances; and implementation and long-term maintenance costs. A consideration such as long-term maintenance cost may manifest itself in a very subjective fashion during the selection process. For example, a BMPs cost may be of very limited interest to the reviewing locality, whereas cost may be the dominant selection criterion in the eyes of a developer. By contrast, the pollutant removal efficiency of a BMP may be necessarily prioritized in the selection process because of the required adherence to governing legislation. These are merely two possible criteria influencing selection. As more and more selection criteria are considered, the task of objectively and optimally selecting a BMP becomes increasingly complex. One mathematical approach for optimization in the face of multiple influential criteria is the Analytic Hierarchy Process. â The analytic hierarchy process (AHP) provides the objective mathematics to process the inescapably subjective and personal preferences of an individual or a group in making a decisionâ (Schmoldt, 2001, pg. 15). This paper details the development of two categories of comprehensive BMP selection matrices expressing long-term pollutant removal performance and annual maintenance and operations cost respectively. Additionally, the AHP is applied in multiple scenarios to demonstrate the optimized selection of a single BMP among multiple competing BMP alternatives. Pairwise rankings of competing BMP alternatives are founded on a detailed literature review of the most popular BMPs presently implemented throughout the United States. / Master of Science
7

ABC - Activity Based Costing e a gestão de projetos no gerenciamento dos custos de manutenção em transporte público de passageiros: um modelo estratégico a partir da cadeia de valor

Maracaja, Flavio 28 August 2015 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-05-04T13:35:26Z No. of bitstreams: 1 arquivototal.pdf: 9161935 bytes, checksum: f754259723418e8bdd6374a6ee8b0b57 (MD5) / Made available in DSpace on 2016-05-04T13:35:27Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 9161935 bytes, checksum: f754259723418e8bdd6374a6ee8b0b57 (MD5) Previous issue date: 2015-08-28 / Passenger transport by bus has a public and notorious importance. A complex logistics chain that by integrating the urban fabric, affects the productivity of production systems due to their own productivity. In this segment, business and government are challenged to fund transport systems that can meet their needs and those of the society. Increased competitiveness, combined with political and social challenges strategically focuses the measures on maintenance costs, still few explored. Traditional ways of funding do not consider all the complexity around its accuracy. In the era of knowledge, the activities managed by projects are the most whose added value. The Activity Based Costs, as most accurate method, details the complexity of these costs. As management support maintenance costs, the exploratory research applies a model, specifically developed, integrating the GP and the ABC. In this sense it has been developed a chain of Generic Value in Public Transport, and a chain of Specific Maintenance value. Maintenance operations and support activities were mapped and grouped into macro activities (set of services / maintenance tasks). The search database, contained in materials services and requisition orders was collected via SQL (Structured Query Language) and documentary research, and validated by interviews. Evidence from a case study in two companies of João Pessoa / Brazil validate the model, presenting management indicators and details the actual maintenance costs throughout its value chain in three stages: cost of services, cost of vehicles and cost of operating lines. Thus, from the case study it can be said that the model, not being single, not definitive, It is effective in maintenance of public transport processes, the accuracy of the results. Even not allowing full generalizations, it is adhering to processes of transport maintenance to keep similar aspects. The application of modern costing methods such as ABC associated with the Project Management (GP), in fact it resulted in a management support maintenance costs in public passenger transport. / O transporte de passageiros por ônibus é de importância pública e notória. Uma complexa cadeia logística que ao integrar o tecido urbano, afeta a produtividade dos sistemas de produção em razão de sua própria produtividade. Nesse segmento, empresas e governo são desafiados a custear sistemas de transportes que possam atender as suas demandas e as da sociedade. O aumento da competividade, aliado a desafios políticos e sociais focam estrategicamente as ações em torno dos custos de manutenção, parcela ainda pouco explorada. As tradicionais formas de custeio não consideram toda a complexidade em torno de sua acurácia. Na era do conhecimento as atividades gerenciadas por projetos são as que mais adicionam valor. O Activity Based Costs como método mais acurado detalha a complexidade desses custos. Como suporte ao gerenciamento dos custos de manutenção, a pesquisa de natureza exploratória aplica um modelo, especificamente desenvolvido, integrando o GP e o ABC. Nesse sentido foram desenvolvidas uma Cadeia de Valor Genérica em Transporte Público e uma Específica de Manutenção. As operações de manutenção e as atividades de apoio foram mapeadas e agrupadas em macroatividades (conjunto de serviços/tarefas de manutenção). A base de dados da pesquisa, contidos em Ordens de Serviços e Requisição de Materiais foi coletada via SQL (Structured Query Language) e pesquisa documental e validada por entrevistas. Evidências a partir de um estudo de caso, em duas empresas de João Pessoa/Brasil validam o modelo que apresenta indicadores de gerenciamento e detalha os reais custos de manutenção ao longo de sua cadeia de valor em três estágios: custos dos serviços, custo dos veículos e custo das linhas operacionais. Logo, a partir do caso em estudo é possível afirmar que o modelo, não se constituindo único, nem definitivo, ressalva-se, é eficaz em processos de manutenção de transporte público pela acuracidade dos resultados. Mesmo não permitindo generalizações plenas, é aderente a processos de manutenções de transportes que mantenham semelhantes aspectos. A aplicação de métodos de custeios modernos como ABC associado à Gestão de Projetos, de fato resultou um suporte ao gerenciamento dos custos de manutenção em transporte público de passageiros.
8

Systém údržby výrobního zařízení ve firemní praxi / Maintenance system of a manufacturing line

Němeček, Jakub January 2017 (has links)
This thesis deals with the design of a new maintenance system of a powder coating line at ABB. The theoretical part describes history of maintenance, used maintenance methods, and types of organizational structure. The practical part describes the current state of maintenance of the production line, analysis of the situation, and subsequently design of the new maintenance system.
9

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.
10

Custos de manutenção em HIS construídas com o sistema inovador de parede de placas moldadas in loco: um estudo de casos no conjunto Mariz I em João Pessoa-PB

Silva, Maisa Beatriz Marinho Fausto da 31 March 2016 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2017-07-20T13:50:17Z No. of bitstreams: 1 arquivototal.pdf: 3151113 bytes, checksum: 11e87c35ec2899531a26a1da6a8d7bd0 (MD5) / Made available in DSpace on 2017-07-20T13:50:18Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3151113 bytes, checksum: 11e87c35ec2899531a26a1da6a8d7bd0 (MD5) Previous issue date: 2016-03-31 / Financiadora de Estudos e Projetos - Finep / The buildings are degraded over time, requiring therefore performing maintenance services. These services generate costs, which are the maintenance costs. And when you speak of the study of maintenance costs in Social Housing, this is a little explored subject, and when it comes to the ones which were built with some innovative/ unconventional building system even more. From the knowledge of this gap in terms of maintenance costs on Social Housing and starting from this scenario this dissertation addresses the issue of maintenance costs in Social Housing that used the innovative building system of "sealing walls in molded concrete slabs on site" from the district Mariz I, located in João Pessoa-PB. For the elaboration of the aforementioned dissertation the approach method was deductive, we used the techniques of direct and indirect documentation (extensive) and was adopted probabilistic sampling process. The research that was carried out and has as product this dissertation is classified as to nature, in quantitative, as the purpose in applied, as the type, descriptive and on the design, in survey research. This work proposes to detail all the items that have undergone maintenance over the years studied in the Social Housing addressed, as well as costs arising from this activity, called actual costs; seeking in prior, with the known values of maintenance expenditures, to project itself in terms of future costs for a given period in each case, from the development of a measurement tool for the maintenance costs that uses the principle of cost-significant item (CSI) and aided by statistical mechanisms. However, as the work progressed other relevant factors were becoming notorious, such as the influence of socioeconomic status of the buildings residents with maintenance costs; the calculation of the cost items that were not done maintenance work, but it was found the need to be made, those called potential costs; the perception of the buildings conservation status in the optics of quality of maintenance practice, among others. In general it was found that the maintenance of the activity was carried out informally and in corrective manner. It has been seen that 22% of maintenance items contributed to 95% of the actual costs of the analyzed buildings. The paint item was the most representative, in terms of effective maintenance costs. About the potential costs, in the most of dwellings, there was a tendency of proportional reversal of the amount thereof compared to actual costs. The values of the maintenance costs were directly proportional to the purchasing power of residents, income limitations of these influenced the absence / postponement of the building’s maintenance, and also in the final result of their execution. / As edificações sofrem degradação com o tempo, necessitando, portanto, da realização de serviços de manutenção. Esses serviços geram despesas, que são os custos de manutenção. E quando se fale do estudo dos custos de manutenção em HIS, este é um assunto pouco explorado, e se tratando das que foram construídas com algum sistema construtivo inovador/não convencional ainda mais. A partir do conhecimento desta lacuna em termos de custos de manutenção em HIS e partindo desse panorama a presente dissertação aborda a questão dos custos de manutenção em HIS que utilizaram o sistema construtivo inovador de “paredes de vedação em placas de concreto moldadas in loco” do conjunto Mariz I, localizado na cidade de João Pessoa- PB. Para a construção da supracitada dissertação o método de abordagem utilizado foi o dedutivo, foram utilizadas as técnicas de documentação indireta e direta (extensiva) e foi adotado o processo de amostragem probabilista. A pesquisa que foi realizada e tem como produto esta dissertação, classifica-se quanto à natureza, em quantitativa, quanto à finalidade em aplicada, quanto ao tipo em descritiva e quanto ao delineamento, em pesquisa de levantamento. Este trabalho se propôs a detalhar todos os itens que sofreram manutenção ao longo dos anos estudados nas HIS abordadas, bem como os custos oriundos desta atividade, denominados de custos efetivos; buscando a priori com os valores conhecidos dos gastos com manutenção se projetar apenas em termos de custos futuros para um dado período em cada caso específico, a partir do desenvolvimento de uma ferramenta de mensuração de custo de manutenção que utiliza-se do princípio de itens custos significativos (CSI) e auxiliada por mecanismos estatísticos. No entanto, à medida que se deu o andamento do trabalho outros fatores relevantes foram se tornando notórios, tais como: a influência da situação socioeconômica dos moradores das edificações com os custos de manutenção; o cálculo dos custos de itens em que não foram feitas intervenções de manutenção, mas que se constatou a necessidade de serem feitas, estes denominados de custos potenciais; a percepção do estado de conservação das edificações na ótica da qualidade da prática da manutenção, entre outros aspectos. Em linhas gerais constatou-se que a atividade de manutenção, foi realizada informalmente e de maneira corretiva. Foi visto que 22% dos itens de manutenção contribuíram com 95% dos custos efetivos das edificações analisadas. O item pintura foi o mais representativo, em termos de custos efetivos de manutenção. Sobre os custos potenciais, na maioria das moradias, há uma tendência de inversão proporcional do montante destes, em relação aos custos efetivos. Os valores dos custos de manutenção foram diretamente proporcionais ao poder aquisitivo dos moradores, as limitações de renda destes influenciaram na ausência/protelação da manutenção das edificações, mas também no resultado final da sua execução.

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