• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 15
  • 11
  • 11
  • 4
  • 4
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 59
  • 59
  • 14
  • 13
  • 9
  • 9
  • 8
  • 7
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 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.
41

Supervisión y control de obras de edificación bajo los enfoques de Lean Construction y del PMI / Supervision and control of works in building construction under the Lean Construction and PMI approaches

Cary Teves, Walter Melvin 17 November 2018 (has links)
El propósito de esta investigación consistió en la realización de una propuesta para la implementación de un sistema de gestión para la apropiada supervisión y control de obras de edificación con base en el trabajo colaborativo. El caso de estudio se basó en la construcción de un hotel en el departamento de Cusco. Para ello fue necesario establecer lineamientos para el desarrollo de la propuesta, luego se describió la metodología de gestión y control utilizado por la supervisión de obra. Se realizó la definición de herramientas de gestión y técnicas de control más convenientes para este propósito. Esta investigación se fundamenta en que la mayor parte de proyectos de edificación son ejecutados descuidando el tiempo, costo, alcance y calidad establecidos; debido a procedimientos inadecuados de supervisión y control. Por otro lado, las controversias y relaciones adversas que se producen entre la supervisión de obra, constructor y cliente, son aspectos que pueden causar impactos significativos en las variables mencionadas. Esta propuesta permite que la supervisión de obra pueda efectuar la entrega integrada del proyecto mediante el trabajo colaborativo, utilizando la metodología del Valor Ganado para una adecuada gestión, y aplicando la técnica del Last Planner para el apropiado control y monitoreo del cronograma y de las actividades en ejecución. Finalmente, se concluye que la aplicación de las herramientas y metodologías expuestas, posibilitan a la supervisión de obra gestionar y controlar apropiadamente el alcance, el cronograma, los costos y la correcta ejecución de todos los trabajos que se realizan en obra. / The purpose of this investigation was to make a proposal for the implementation of a management system for the proper supervision and control of works in building construction based on collaborative work. The case study focuses on the construction of a hotel located in the Cusco department. This required the establishment of guidelines for the development of the proposal, and then it was described the management and control methodology used by the site supervisors. The most convenient management tools and control techniques for this purpose were defined. This research is based on the fact that the majority of building projects are executed neglecting the established time, cost, scope and quality due to inadequate supervision and control procedures. On the other hand, controversies and adverse relationships that occur between supervisors, constructor and owner are aspects that can cause significant impacts on the variables mentioned above. This proposal allows the site supervisors to carry out the integrated project delivery through collaborative work, using the Earned Value Methodology for proper management, and applying the Last Planner technique for proper control and monitoring of the progress of the production activities and protect the stipulated deadline in the project's general schedule. Finally, it is concluded that the application of the exposed tools and methodologies enable the site supervisors properly manage and control the scope, schedule, costs and the correct execution of all the works that are carried out on site. / Trabajo de investigación
42

The Impact of Supply Chain Logistics Performance Index on the Control of Neglected Tropical Diseases in Low- and Middle-Income Countries

Umaru, Farouk Adams 01 January 2015 (has links)
Neglected tropical diseases (NTD) in low- and middle-income countries are still not on target per the World Health Organization's (WHO) elimination goal of 2020. Mass drug administration (MDA) is one of the effective strategies supported by the WHO for the control and subsequent elimination of NTD. This quantitative study explored how supply chain logistic capacity may be hampering MDA coverage in countries in which the diseases are endemic. The study examined secondary data from WHO data bank for MDA coverage, to quantify the relationship between supply chain logistics capacity, as measured by the World Bank's logistics performance index (LPIs), and the control of NTD using MDA. The ecological theory of health behavior was the theoretical framework for this study. The research questions explored whether a low- and/or middle-income country's supply chain infrastructure, logistics services, customs and border procedures, and supply chain reliability, predict the coverage of MDA in controlling NTD. A multiple regression model determined the linear relations between each predictor: supply chain infrastructure (H1), logistics services (H2), custom and border procedures (H3), and supply chain reliability (H4) and the control of neglected diseases as determine by MDA. Results indicated that supply chain capacity, custom and border processes, and supply chain reliability are statistically significant in predictors of MDA coverage in the control of NTD in developing countries. This study may enhance social change by improving supply chain capacity for more effective distribution of PCT drugs, thus helping with the elimination of NTDs and improved health outcomes in low- and middle-income countries.
43

The implementation of selected technologies to enhance the restoration of indigenous tree species in the deforested riparian areas in the Mapungubwe National Park, South Africa : a case study / Yolandi Els

Els, Yolandi January 2010 (has links)
Stretches of forest along the Limpopo and Shashe Rivers have been classified as a unique forest type in the vegetation of South Africa and are considered as being "critically endangered" by the South African Biodiversity Institute. Roughly 400 hectares of this riverine forest area inside the western section of the Mapungubwe National Park (MNP), a UNESCO World Heritage site, were deforested and therefore degraded due to previous agricultural cultivation practices. Given the extent of forest degradation that has occurred, the restoration of this area by means of the re–vegetation of indigenous trees to its former composition is one of the objectives of the MNP's management plan. The successful establishment of tree seedlings, especially in semi–arid systems, is however presented with a wide range of constraints and limiting conditions, which often result in very high mortality rates during restoration projects. An experimental exclosure, as identified by South African National Parks (SANParks), was therefore fenced off inside the degraded old lands to act as a demonstration site for the restoration of indigenous trees. A pilot study conducted in 2006, involved the transplantation of selected indigenous tree species with the aim of evaluating suitable re–vegetation technologies. The research contained in this dissertation was also conducted inside the experimental exclosure, where recommendations derived from the pilot study were evaluated, including the assessment of new re–vegetation technologies to enhance the establishment of the indigenous trees. This study was therefore a follow–up project which involved both field– and greenhouse trials. Seedlings of the following species were either transplanted into the experimental exclosure (field trial) or cultivated inside a controlled environment in the greenhouse at the North–West University: Acacia xanthophloea Benth. (fever tree), Berchemia discolor (Klotzsch) Hemsl. (brown–ivory), Combretum imberbe Wawra (leadwood), Faidherbia albida (Delile) A. Chev. (ana tree), Philenoptera violacea (Klotzsch) Schrire (apple–leaf), Salvadora australis Schweick. (narrow–leaved mustard tree) and Xanthocercis zambesiaca (Baker) Dumaz–le–Grand (nyala tree). During the follow–up study the effects of various enhancement treatments were tested regarding the survival, growth and physiological performance of seedlings in both the field– and greenhouse trials. The enhancement treatments consisted of the addition of compost and indigenous arbuscular mycorrhizal fungi (AMF). In addition, seedlings transplanted during the pilot study, which did not include enhancement treatments, were also monitored for establishment and growth. The potential use of established Acacia tortilis Hayne trees to facilitate growth and establishment and to act as "nursing plants", was also assessed. In addition, various pre–sowing treatments were also applied to seeds of selected tree species in the greenhouse to assess the germination rate. The survivorship and growth of seedlings in both the field– and greenhouse trial were determined by using three growth parameters, namely "stem diameter at the base", "stem diameter 30 cm from the base", and "height of the tree in its natural growth form". Chlorophyll fluorescence induction (JIP test) was measured on seedlings in both trials, using the multi–parametric expression, namely performance index (PIABS), as a measure of the overall vitality of the plants of each species–treatment combination. Physical and chemical analyses were carried out on the soil inside the experimental exclosure. Basic descriptive statistics were used to analyse seedling survival and germination rates, and a two–way analysis of variance (ANOVA) was used to determine the statistical significant effects of the various enhancement treatments on diameter growth in each species (p < 0.05). Fluorescence data were processed using the Biolyzer software and significant effects in each species were determined using the Student's t–test (p < 0.05). Multivariate data ordinations using the CANOCO package were used to determine the differences in soil types inside the experimental exclosure. Moisture stress due to transplantation shock, competition with dense grass cover and herbivory, resulted in an overall 55.8% seedling survival rate and negative stem diameter growth for transplanted seedlings in the field. In comparison, seedlings cultivated in the greenhouse had much higher survival rates and showed positive stem diameter growth. Most species in the greenhouse showed higher growth rates and significantly higher vitality values when planted with enhancement treatments. The responses of transplanted seedlings to the enhancement treatments were very species–specific in the field trials. Based on these results, it was concluded that the enhancement treatments were beneficial with regard to the establishment and growth of most of the species. The beneficial effect was however cancelled out by the various abiotic and biotic factors encountered in the natural environment. Seedlings transplanted in the understory of established pioneer A. tortilis trees had much lower survival rates as the extensive root system of A. tortilis most likely out–competed the transplanted seedlings for moisture and nutrients. Many seedlings were also predated by insects or small mammals which reduced the growing potential. The germination trials recorded the highest germination rates for most species when germinated in the compost–containing treatments. These trials also indicated that all of the investigated species showed higher survival rates when pre–sowing treatments, such as soaking, mechanical scarification and removing the seed from fruit, were applied. Various recommendations emphasising long–term monitoring, proper maintenance and after–care of future restoration efforts are made. These include experimental layout of exclosure plots and pretransplantation treatments of seedlings while cultivated in the nursery. During this study, the experimental exclosure was also used as a demonstration site for training and capacity building for SANParks personnel and students from academic institutions. / Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
44

The implementation of selected technologies to enhance the restoration of indigenous tree species in the deforested riparian areas in the Mapungubwe National Park, South Africa : a case study / Yolandi Els

Els, Yolandi January 2010 (has links)
Stretches of forest along the Limpopo and Shashe Rivers have been classified as a unique forest type in the vegetation of South Africa and are considered as being "critically endangered" by the South African Biodiversity Institute. Roughly 400 hectares of this riverine forest area inside the western section of the Mapungubwe National Park (MNP), a UNESCO World Heritage site, were deforested and therefore degraded due to previous agricultural cultivation practices. Given the extent of forest degradation that has occurred, the restoration of this area by means of the re–vegetation of indigenous trees to its former composition is one of the objectives of the MNP's management plan. The successful establishment of tree seedlings, especially in semi–arid systems, is however presented with a wide range of constraints and limiting conditions, which often result in very high mortality rates during restoration projects. An experimental exclosure, as identified by South African National Parks (SANParks), was therefore fenced off inside the degraded old lands to act as a demonstration site for the restoration of indigenous trees. A pilot study conducted in 2006, involved the transplantation of selected indigenous tree species with the aim of evaluating suitable re–vegetation technologies. The research contained in this dissertation was also conducted inside the experimental exclosure, where recommendations derived from the pilot study were evaluated, including the assessment of new re–vegetation technologies to enhance the establishment of the indigenous trees. This study was therefore a follow–up project which involved both field– and greenhouse trials. Seedlings of the following species were either transplanted into the experimental exclosure (field trial) or cultivated inside a controlled environment in the greenhouse at the North–West University: Acacia xanthophloea Benth. (fever tree), Berchemia discolor (Klotzsch) Hemsl. (brown–ivory), Combretum imberbe Wawra (leadwood), Faidherbia albida (Delile) A. Chev. (ana tree), Philenoptera violacea (Klotzsch) Schrire (apple–leaf), Salvadora australis Schweick. (narrow–leaved mustard tree) and Xanthocercis zambesiaca (Baker) Dumaz–le–Grand (nyala tree). During the follow–up study the effects of various enhancement treatments were tested regarding the survival, growth and physiological performance of seedlings in both the field– and greenhouse trials. The enhancement treatments consisted of the addition of compost and indigenous arbuscular mycorrhizal fungi (AMF). In addition, seedlings transplanted during the pilot study, which did not include enhancement treatments, were also monitored for establishment and growth. The potential use of established Acacia tortilis Hayne trees to facilitate growth and establishment and to act as "nursing plants", was also assessed. In addition, various pre–sowing treatments were also applied to seeds of selected tree species in the greenhouse to assess the germination rate. The survivorship and growth of seedlings in both the field– and greenhouse trial were determined by using three growth parameters, namely "stem diameter at the base", "stem diameter 30 cm from the base", and "height of the tree in its natural growth form". Chlorophyll fluorescence induction (JIP test) was measured on seedlings in both trials, using the multi–parametric expression, namely performance index (PIABS), as a measure of the overall vitality of the plants of each species–treatment combination. Physical and chemical analyses were carried out on the soil inside the experimental exclosure. Basic descriptive statistics were used to analyse seedling survival and germination rates, and a two–way analysis of variance (ANOVA) was used to determine the statistical significant effects of the various enhancement treatments on diameter growth in each species (p < 0.05). Fluorescence data were processed using the Biolyzer software and significant effects in each species were determined using the Student's t–test (p < 0.05). Multivariate data ordinations using the CANOCO package were used to determine the differences in soil types inside the experimental exclosure. Moisture stress due to transplantation shock, competition with dense grass cover and herbivory, resulted in an overall 55.8% seedling survival rate and negative stem diameter growth for transplanted seedlings in the field. In comparison, seedlings cultivated in the greenhouse had much higher survival rates and showed positive stem diameter growth. Most species in the greenhouse showed higher growth rates and significantly higher vitality values when planted with enhancement treatments. The responses of transplanted seedlings to the enhancement treatments were very species–specific in the field trials. Based on these results, it was concluded that the enhancement treatments were beneficial with regard to the establishment and growth of most of the species. The beneficial effect was however cancelled out by the various abiotic and biotic factors encountered in the natural environment. Seedlings transplanted in the understory of established pioneer A. tortilis trees had much lower survival rates as the extensive root system of A. tortilis most likely out–competed the transplanted seedlings for moisture and nutrients. Many seedlings were also predated by insects or small mammals which reduced the growing potential. The germination trials recorded the highest germination rates for most species when germinated in the compost–containing treatments. These trials also indicated that all of the investigated species showed higher survival rates when pre–sowing treatments, such as soaking, mechanical scarification and removing the seed from fruit, were applied. Various recommendations emphasising long–term monitoring, proper maintenance and after–care of future restoration efforts are made. These include experimental layout of exclosure plots and pretransplantation treatments of seedlings while cultivated in the nursery. During this study, the experimental exclosure was also used as a demonstration site for training and capacity building for SANParks personnel and students from academic institutions. / Thesis (M.Sc. (Environmental Science))--North-West University, Potchefstroom Campus, 2011.
45

網路廣告業核心競爭力與營運模式之探討—以A公司為例 / A research of core competence and business model for the internet-base advertising industry - Sample of a company

楊家南 Unknown Date (has links)
當網路普及並進入日常生活之後,傳統的企業核心競爭力與其營運模式便產生了根本的變化,尤其是那些利用網路為銷售通路的相關產業。由於網路科技的發達,大幅縮減了企業核心競爭力的適應年限,創新與改革成為在這瞬息萬變的經營環境中,能夠生存的重要因素與條件。 本研究試圖藉由探討網路媒體產業的市場特性與其經營環境之變遷,從而歸納整理出個案公司原有的核心競爭力與營運模式,藉由導入分析工具,加以分析,以便尋找出可供其未來發展之關鍵因素,並對相關的營運模式做深入的探討,找出目前發展困境的可能因素,給予建議與結論。 而分析核心競爭力的方式,則從與個案公司營運模式相關的構面開始。基本上,每一個構面,都會互相影響,因此可以從表格的分析中,試圖知道目前個案公司營運模式的問題所在。設計重點在於從企業經營者所期望達到的目標,分別設計出可量化的績效指標,並連結其相對應的實際成果與相關評估量度,再經由量化績效指標的強度,得到衡量結果,進而找到關鍵成功因素,針對這些關鍵問題,加以系統化的分析,並嘗試給予相關建議,相信這對於提高公司營運的競爭優勢,將有所助益。 / Internet changes the world. The core competence with business model for traditional company has been changed from inside. Since technology for Internet grows up so fast, innovation and reform are the key factors for business survival. The main purpose of this research will have the comment and suggestion from the predicament of the example company operation within business market and/or environment of network media industry. Based on the tool to analyze the status of the example company, we will find out the key success factors for its development. First of all for analysis, it will begin from perspectives of business operation and core competence related since all perspectives are interaction. We will have the result for key success factors after target and performance index been measured. In response to analyze status and give recommendations of these key issues, I believe it would be helpful for improving the company’s competitive advantage.
46

Utilização de indicadores convencionais e de satisfação dos usuários para avaliação da qualidade do serviço de abastecimento de água na cidade de Campina Grande/PB.

MEDEIROS, Luísa Eduarda Lucena de. 27 July 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-27T12:15:33Z No. of bitstreams: 1 LUÍSA EDUARDA LUCENA DE MEDEIROS - DISSERTAÇÃO (PPGECA) 2017.pdf: 2318998 bytes, checksum: a10de376910ac93a77b155d2faff276d (MD5) / Made available in DSpace on 2018-07-27T12:15:33Z (GMT). No. of bitstreams: 1 LUÍSA EDUARDA LUCENA DE MEDEIROS - DISSERTAÇÃO (PPGECA) 2017.pdf: 2318998 bytes, checksum: a10de376910ac93a77b155d2faff276d (MD5) Previous issue date: 2017-03-10 / Um dos grandes desafios enfrentados pelas concessionárias responsáveis pelo abastecimento de água nos centros urbanos é a prestação de um serviço de qualidade sob os aspectos de infraestrutura, operação, manutenção de redes, qualidade da água oferecida, satisfação do usuário atendido, entre outros. Com usuários cada vez mais atentos e defensores de seus direitos, as concessionárias necessitam de critérios mais rigorosos para garantirem um atendimento dentro dos padrões mínimos estabelecidos por lei. Com o intuito de colaborar com a melhoria do serviço de abastecimento oferecido à população, o presente trabalho propôs o desenvolvimento de um índice de desempenho do serviço de abastecimento de água na cidade de Campina Grande - Paraíba (IDSA-CG). Foram estudados 22 indicadores divididos em cinco categorias: operacional, econômico-financeira, qualidade, infraestrutura e recursos humanos. Dentre os indicadores selecionados está o de satisfação do usuário, proposto neste trabalho, a partir do levantamento, em todos os bairros da cidade, da percepção da população a respeito do serviço oferecido pela concessionária e incorporado aos demais para compor, o mais fielmente possível, o IDSA–CG. Os resultados referentes ao estudo individual dos indicadores mostraram que os indicadores de infraestrutura (extensão e cobertura de rede) e qualidade da água (incidência de cloro, turbidez e coliformes totais e conformidade de quantidade de amostras) apresentaram valores positivos, próximos ou iguais aos limites superiores definidos na pesquisa. As maiores deficiências do serviço foram associadas aos indicadores operacionais (perdas na distribuição, macromedição, consumo médio de água e consumo de energia) apontando para necessidade de melhoria na operacionalidade do sistema e os indicadores econômico-financeiros (tarifas médias, evasão de receitas e despesas com energia elétrica) que alertam para uma maior fiscalização das ligações clandestinas de água e um melhor monitoramento da inadimplência dos usuários. Quanto aos indicadores de recursos humanos, o resultado mais divergente do esperado foi obtido para a produtividade de pessoal total, indicando um número de funcionários por ligações de água abaixo da média brasileira. O indicador de satisfação apresentou um valor de 45,44% que mostrou um usuário medianamente satisfeito com o serviço oferecido pela empresa distribuidora de água na cidade. Finalmente, a partir dos indicadores escolhidos, pode-se obter o IDSA-CG e conclui-se que o serviço atualmente disponibilizado à cidade de Campina Grande é classificado como REGULAR, sendo necessárias medidas estruturantes e administrativas para a melhoria da gestão do mesmo. / One of the biggest challenges faced by the water utilities in the urban areas is to provide a quality service regarding aspects such as infrastructure, operation, network maintenance, quality of delivered water, users’ satisfaction etc. As the users pay more attention and stand for their rights more and more, the water utilities tend to make use of more strict criteria to guarantee that the service fulfills the minimum standards stablished by the current legislation. In order to cooperate for an improvement in the supply service offered to the population, this study suggests the development of a performance index for the water supply service in the city of Campina Grande – Paraíba (IDSA-CG). To achieve this, 22 indicators were studied and divided into five categories: operational, economic/financial, quality, infrastructural and human resources. Among the selected indicators to this study, there is one called user’s satisfaction, which was created based on a survey, in all neighborhoods of the city, to know the population’s perspective about the service provided by the water utility and, thus, being incorporated to the other indicators in order to form, as faithfully as possible, the IDSA-CG. The results related to the individual study of the indicators showed that the infrastructural indicators (network extension and coverage) and the water quality indicator (incidence of chlorine, turbidity and total coliforms, as well as conformity with sample quantity) obtained optimum values, close or equal the superior limits defined in the research. The main service drawbacks are associated to the operational indicators (losses in the distribution, macro measurement, average water consumption and energy consumption), with a need to improve the system operation, and also to the economic/financial indicators (average water charges, income evasion and electricity expenses), with a more efficient demand to trace clandestine water connections and to monitor the users in debt. Regarding the human resources indicators, the most divergent outcome compared to the expected result refers to the total employee productivity, which indicated a number of employees per water connections below the Brazilian average. The satisfaction indicator obtained a result of 45,44%, which means that the user is fairly satisfied with the service offered by the water utility in the city. Finally, based on the selected indicators, it was possible to calculate the IDSA-CG and the service currently available to the city of Campina Grande can be classified as REGULAR, with the need to introduce structural and administrative measures in order to perform a better system management.
47

Análisis de costos de no calidad en edificaciones multifamiliares masivas caso: Nuevo Alcázar Condominio

Guevara Contreras, Gremy Yeleny, Santillán Atoche, Nery Maritza Angélica January 2015 (has links)
La presente tesis tiene como objetivo ser guía en el análisis e interpretación de las causas de los Costos de No Calidad para los futuros proyectos del sector construcción, tomando como fuente de información el proyecto de viviendas multifamiliares: “Nuevo Alcázar Condominio”, ubicada en el distrito del Rímac en la ciudad de Lima. La tesis se desarrolló de acuerdo a la información de la Primera Etapa comprendida por los Edificios 17, 18 y 19; las principales fuentes de información fueron los registros de las No Conformidades en el proceso de ejecución de la obra, la data del programa S10 que nos fue de ayuda para obtener los costos reales acumulados, la data del programa PLANOK, del cual se obtuvo el registro de observaciones de los propietarios desde la puesta en servicio del proyecto, el reporte operativo de costos acumulado a Agosto 2015, el registro de adicionales y control de cambios durante la ejecución del proyecto, estas herramientas fueron piezas claves para el análisis de esta investigación. Para el caso estudiado, se concluyó del objetivo general que los costos de no calidad influyen en el margen de utilidad cuando se realiza un presupuesto sincerado, de los objetivos específicos se concluye que la calidad se debe desarrollar desde el diseño del proyecto y no solo durante la etapa de ejecución, ya que los errores o incompatibilizaciones en los planos generan adicionales de obra y se analizaron que las partidas de control que representaron una mayor ganancia fueron las que obtuvieron mayores observaciones en la puesta en servicio del proyecto. The objective of this investigation is to be a guide in the analysis and interpretation of the causes of non-quality costs for future projects in the construction sector, using as information the project: “Nuevo Alcázar Condominio", located in the district of Rimac in Lima. The investigation was developed according to information of the first phase comprised of Buildings 17, 18 and 19; the main sources of information were records of nonconformity in the process of execution of the project, the data of the S10 program that was helpful to us for actual costs accumulated, dates from PLANOK program, which recording observations of the owners was obtained from the commissioning of the project, operating costs accumulated report in August 2015, additional registration and change control during project implementation, these were important tools for the analysis of this research. For the case study, it was concluded from general object that the costs of not quality affect the profit margin when the budget is exact, the specific objectives that quality is important from the design of the project and not only in the implementation phase, so that the fault on drawings generate additional work and we analyzed the control items accounted for a larger gain were the major observations obtained in the service of the project.
48

An investigation of the level of selected trace metals in plant species within the vicinity of tantalum mining area in Gatumba, Ngororero District, Rwanda

Gakwerere, François 02 April 2013 (has links)
Due to mining activities, the natural vegetation cover in Gatumba area was removed and replaced either by crops or bare wasteland with reduced available arable land. The main aim of the study was to assess the impact of the mining activities on the plant mineral uptake and the dynamics of the vegetation. The vegetation in this area under investigation was diversified and heterogeneous. Trace element concentrations in soils were similar to those in plant parts but some elements were highly concentrated in soils than in plants. According to the bioaccumulation factors of the analyzed trace elements in plant parts, two categories of plants were identified, and these are excluders and accumulators. No toxic levels of the evaluated trace elements were found in the analyzed plant samples. As a recommendation for the adaptation of plants to Gatumba mining environment, the most useful plant species for the revegetation/restitution of the technosols should be Sesbania sesban, Crotalaria dewildemaniana and Tithonia diversifolia subject to further experiments on trace elements bioaccumulation and organic matter production / Environmental Sciences / M.A. Science (Environmental Sciences)
49

產學合作技術移轉過程之績效影響因素研究

林文淵, Lin, Wenyuan Unknown Date (has links)
近年來,在全球化市場競爭之衝擊下,企業競爭日益激烈,誰能較早取得關鍵技術,並將之轉化為公司內部的技術能力,將是一個公司開拓或保有市場的一項關鍵因素;對那些知識及技術本位的企業,更是如此。然而,在如此激烈競爭的環境中,為求快速、正確且有效率的取得技術知識,已無法由企業內部獨自完成。據此,尋求外部的技術知識來源已是企業決策者所必須正視的課題。 因此,就國內的企業研究環境而言,如何運用產學合作機能,利用學校與企業資源,雙方在合作上發揮科技資源整合互補效應,以減少學校基礎研究與企業應用研究之間的差距。不過,為何在同一個研究單位,執行技術移轉的績效成果有顯著的差異。什麼是產學績效的評定標準、什麼是它影響技術移轉執行的顯著因子、它們之間的關係如何?本研究討論主軸專注在專案技術移轉執行過程。 目前國內及國外對於產學合作的相關研究很多,有些學者對於產學合作的機制、動機、合作成效、關鍵成功因素作討論;也有些學者針對某特定區域中的產學合作現況作研究,但是研究方向大多以學校的角度評估產學合作的績效,很少看到以公司研究單位的角度來了解影響因子。因而,由公司端探究企業影響產學合作執行績效的要素,也是本研究另一個特色。 希望藉由影響執行過程的因素和績效這兩個構面,所產生的問題,逐一的討論,希望能了解這些因子的因果關係。在未來產學合作專案中,加強做好不足的地方。使合作的結果更加理想。 / In recent years, it’s a key factor for a company to develop or to keep market by getting a core technology earlier and converting it into a company’s internal technical competence. Such scenario is also applied for those enterprises which are knowledge and technology -oriented. However, it is very difficult for an enterprise alone to get a core technology promptly, correctly and efficiently under highly competitive environment. Therefore, seeking outer source of technical knowledge is an essential lesson for an entrepreneur. As for domestic setting of enterprise’s research, it is important to shorten the gap between academic theoretical research and industrial applied research through integrating technical resources from both university and enterprise to obtain compensatory effects for each other on the cooperative basis. However, there is an obvious discrepancy on the performance of executing technical transfer in the same research unit. What are the criteria for evaluating industrial performance and academic one? What are the obvious factors which affect execution of technical transfer? And what are their relationships? This research focuses on the executive process of technical transfer. There are many domestic and foreign researches done on the topic of cooperation between the industry and the academy. Some scholars have discussed about the system, motive, result and key successful factor of the cooperation between the industry and the academy. Some other scholars have done research on present situation of cooperation between the industry and the academy in certain area, but many researches have been done in the academic way of evaluating performance of cooperation between the industry and the academy. Fewer researches have been done in the industrial way of estimating the influential factors. Another special feature of this research is the executive performance of cooperation between the industry and the academy could be affected by the industry. I hope those problems caused by the factors which affect the executive process and its performance can be discussed individually, and the relationship between cause and effect can be understood properly. Also, I wish I can do well in those areas needed to be enhanced in the future project of cooperation between the industry and the academy, and make it better for the result of such cooperation.
50

Contribution à la tolérance active aux défauts des systèmes dynamiques par gestion des références / Contribution to active fault tolerance of dynamic systems based reference management

Boussaïd, Boumedyen 09 July 2011 (has links)
Le sujet de cette thèse s'inscrit dans le cadre des systèmes tolérants aux défauts sous contraintes avec prise en considération de la dégradation des performances. L'objectif principal de ce travail consiste à considérer la gestion des références comme une partie intégrante du système de commande tolérant aux défauts. Dans la littérature, la plupart des méthodes actives de tolérance aux défauts supposent que le recouvrement du système nominal est toujours possible et que les performances nominales sont toujours atteignables. Cette condition est peu réaliste dans la pratique puisque plusieurs éléments empêchent le système reconfiguré de revenir à son mode de fonctionnement nominal. Dans le domaine industriel, l'ensemble des contraintes du système est un handicap majeur qui limite le fonctionnement nominal d'un système à des plages fonctionnelles bien définies. Ces plages fonctionnelles sont énormément réduites après l'apparition de certains défauts dits sévères et qui affectent généralement les actionneurs. Par conséquent, cette hypothèse de recouvrement des performances nominales dans le cas des systèmes sous contraintes limite l'ensemble des défauts traités par ces méthodes classiques à quelques défauts dits mineurs. Afin de remédier a ce problème, une architecture de reconfiguration structurée en deux niveaux est proposée. Le premier concerne les algorithmes classiques de reconfiguration en agissant sur un contrôleur reconfigurable, et le deuxième agit sur le module de gestion des références conçu à base d'un gouverneur de référence avec offset. La connaissance exacte du modèle en post-défaut nécessite un système de détection et diagnostic de défaut qui permet d'estimer l'amplitude de défaut, ce qui conduit à la synthèse d'un observateur adaptatif d'estimation de défaut à base de LMI. Afin de synchroniser le déroulement du processus FTC, deux indices ont été conçus. Le premier indice porte sur le mécanisme de décision permettant de sélectionner le/les niveau(x) de reconfiguration nécessaire(s) à l'accommodation du défaut. Le deuxième indice permet d'évaluer le niveau de dégradation du système « post-défaut ». Une dégradation de performance est toujours admise tant que les consignes de sécurité sont respectées / The subject of this thesis is part of fault tolerant control systems under constraints with consideration of performance degradation. The main objective of this work is to consider the reference management as an integral part of the fault tolerant control system. In the literature, the most active methods of fault tolerance imply that recovery of the nominal system is always possible and that performance ratings are still achievable. This requirement is unrealistic in practice because several factors prevent the system reconfigured back to its nominal operating mode. In industry, the set of system constraints is a major problem which limits the nominal operating of the system to defined functional ranges. These functional ranges are reduced dramatically after the occurrence of some faults known as severe faults that generally affect the capacity of actuators. Therefore, this assumption of nominal performance recovery in the case of systems under constraints limits the set of faults treated with these conventional methods to a few minor faults. To remedy this problem, architecture of reconfiguration structured in two levels is proposed. The first level concerns the conventional reconfiguration algorithms acting on a reconfigurable controller, and the second acts on the module of reference management based on a reference-offset governor. The exact knowledge of the post-fault model requires a fault detection and diagnosis system to estimate the magnitude of fault, which led to the synthesis of an adaptive observer based LMI for estimating fault. To synchronize the FTC process flow, two indices have been designed. The first index refers to the decision mechanism for selecting the reconfiguration level required for the accommodation of the fault. The second index used to evaluate the level of the degradation of the system "post-fault". The performance degradation is still allowed as long as safety instructions are respected

Page generated in 0.0662 seconds