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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.
201

Fungicide sensitivity and spatial and temporal dynamics of Botrytis cinerea and Colletotrichum spp. in conventional and organic strawberry fields / Sensibilidade a fungicidas e dinâmicas espacial e temporal de Botrytis cinerea e Colletotrichum spp.em campos de morangueiro convencionais e orgânicos

Juliana Silveira Baggio 28 September 2016 (has links)
Botrytis and Anthracnose fruit rots, caused by Botrytis cinerea and Colletotrichum spp., respectively, are major strawberry diseases. This study aimed to compare organic and conventional strawberry production systems by evaluating the sensitivity of B. cinerea and Colletotrichum spp. isolates to the main single-site fungicides used in Brazil and by characterizing the spatial and temporal dynamics of the diseases caused by these pathogens using epidemiological tools. Isolates were collected from conventional and organic fields in four different Brazilian states from 2013 to 2015. Resistance to azoxystrobin, iprodione and thiophanate-methyl was found in B. cinerea isolates with EC50 values higher than 71.9, 688 and 1.2 μg/ml, respectively. Resistance to the aforementioned fungicides was observed in 87.5, 76.6 and 92.2 % of isolates from conventional fields, and 31.4, 22.9 and 51.4 % of isolates from organic fields, respectively. Moreover, frequencies of populations with multiple fungicide resistance to the three active ingredients were 75 and 8.6 %, with no resistance to any of the fungicides were 6.25 and 34.3 % for isolates collected from conventional and organic areas, respectively. Molecular analyses of the cytochrome b, beta-tubulin and bos1 genes revealed, respectively, the presence of G143A, E198A and I365N/S, Q369P or N373S mutations in resistant populations of B. cinerea. Fungicides sprayed preventively on strawberry fruit inoculated with B. cinerea failed to control resistant isolates. Isolates of C. acutatum resistant to azoxystrobin and difenoconazole were not observed. Mean EC50 values for isolates collected from organic fields were 0.44 and 0.95 μg/ml, and from conventional areas were 0.629 and 0.107 μg/ml for azoxystrobin and difenoconazole, respectively. Populations of C. acutatum showed insensitivity to thiophanate-methyl rather than resistance and EC50 values could not be determined. None of the isolates contained the most common mutations associated with fungicide resistance. The temporal and spatial dynamics of Botrytis and Anthracnose fruit rots were characterized in the 2015 strawberry season in conventional and organic farms. Temporal progress models were fitted to the cumulative incidence of diseased strawberry fruit or plants over time with non-linear regressions. The spatial pattern of the diseases was analyzed according to the index of dispersion (D), the index of aggregation (V/M), and the Taylor\'s power law. The incidence-diseased fruit density relationship was analyzed by fitting a linear model. Fruit with symptoms of Colletotrichum spp. were not observed in the organic area and were found in few assessment dates in the conventional area. Incidence of Botrytis fruit rot in symptomatic fruit and plants were generally well described by the logistic model. The organic area presented disease incidence and daily progress rate higher than the conventional area. The aggregation of diseased fruit on strawberry plants were observed for both areas. Botrytis fruit rot presented similar epidemiological patterns for both conventional and organic areas, however, disease intensity was greater for the organic area; this was likely due to differences in disease control management. This study reinforces the importance for the implementation of integrated management programs in strawberry nurseries and production fields. / Mofo cinzento e antracnose do fruto, causados por Botrytis cinerea e Colletotrichum spp., respectivamente, são as mais importantes doenças em morangueiro. Esse estudo objetivou comparar sistemas de produção orgânico e convencional em morangueiro através da avaliação da sensibilidade de isolados de B. cinerea e Colletotrichum spp. aos principais fungicidas sítio-específicos utilizados no Brasil, e da caracterização das dinâmicas espacial e temporal das doenças com o uso de ferramentas epidemiológicas. Isolados foram coletados em campos convencionais e orgânicos em quatro diferentes Estados brasileiros nos anos de 2013 a 2015. Resistência à azoxistrobina, iprodiona e tiofanato-metílico foi encontrada em isolados de B. cinerea com valores de CE50 maiores que 71,9, 688 and 1,2 μg/ml, respectivamente. Resistência aos fungicidas acima mencionados foi observada em 87,5, 76,6 and 92,2 % dos isolados provenientes de campos convencionais e em 31,4, 22,9 and 51,4 % dos isolados oriundos de campos orgânicos, respectivamente. Além do mais, frequências de populações com resistência múltipla aos três fungicidas foram 75 e 8,6 %; e com nenhuma resistência a qualquer dos produtos, 6,25 e 34,3 % para isolados coletados em campos convencionais e orgânicos, respectivamente. Análise molecular dos genes do citocromo b, beta-tubulina e bos1 revelaram, respectivamente, a presença das mutações G143A, E198A e I365N/S, Q369P ou N373S em populações resistentes. Fungicidas aplicados preventivamente em morangos inoculados com B. cinerea falharam em controlar isolados resistentes. Isolados de C. acutatum resistentes à azoxistrobina e ao difenoconazole não foram observados. Valores médios de CE50 para isolados coletados em campos orgânicos foram 0,44 e 0,95 μg/ml; e para isolados de áreas convencionais, 0,629 e 0,107 μg/ml para azoxistrobina e difenoconazole, respectivamente. Populações de C. acutatum demonstraram insensibilidade ao tiofanato-metílico e valores de CE50 não puderam ser determinados. Nenhum dos isolados analisados continha as mutações comumente associadas à resistência a fungicidas. As dinâmicas temporal e espacial das doenclas causadas por esses patógenos foram caracterizadas na safra de 2015 em campos de morangueiro convencional e orgânico. Modelos de progresso temporal foram ajustados à incidência cumulativa de frutos ou plantas doentes no tempo com regressões não-lineares. O padrão espacial das doenças foi analisado de acordo com o índice de dispersão (D), índice de agregação (V/M) e lei de Taylor. A relação incidência-densidade de frutos doentes foi analisada com o ajuste de um modelo linear. Frutos com sintomas de Colletotrichum spp. não foram observados na área orgânica e foram encontrados em poucos dias de avaliação na área convencional. Incidência de mofo cinzento em frutos e plantas foi bem descrita pelo modelo logístico. A área orgânica apresentou incidência de doença e taxa de progresso diária maiores que da área convencional. A agregação de frutos doentes em plantas foi observada para ambos os locais. O mofo cinzento apresentou padrões epidemiológicos semelhantes para as áreas convencional e orgância, porém com maior intensidade de doença no campo orgânico, provavelmente em decorrência do manejo adotado para controle de doenças. Esse estudo reforça a importância da implementação de programas de manejo integrado de doenças em viveiros de mudas e campos de produção de morangueiro.
202

Contribuição relativa do K de zonas do solo para o conteúdo na soja e plantas em sucessão / Relative contribution of soil K to total contents in soybean plants and succession plants

Danyllo Santos Dias 15 January 2018 (has links)
Esta pesquisa foi realizada com o objetivo de identificar a zona do solo de onde o K foi absorvido e acumulado na soja (safra) e nas plantas em sucessão (segunda safra: milho, braquiária e milho consorciado com a braquiária). Para tanto, utilizou o elemento rubídio (Rb) como marcador do nutriente potássio (K), o qual foi posicionado na superfície do solo, a 30 cm e 60 cm de profundidade. A contribuição relativa de as camadas do solo para a ciclagem de K será assumida como proveniente dos primeiros 30 cm de solo (Rb na superfície), de 30 cm a 60 cm (Rb a 30 cm) e de 60 cm a 90 cm de profundidade (Rb a 60 cm). Ainda, a ciclagem de K foi obtida indiretamente, a partir da recuperação de Rb, com base na hipótese de que a mesma equivale à recuperação de K do solo. O experimento foi realizado na Universidade Federal de Goiás, Regional de Jataí, no ano agrícola 2015/2016. O delineamento experimental foi em blocos casualizados, com parcelas subdivididas e quatro repetições. As parcelas constituem os sistemas de produção (soja, soja/milho, soja/braquiária e soja/milho-braquiária), e as subparcelas correspondem às profundidades onde foi posicionado o Rb (superfície do solo, 30 e 60 cm de profundidade). Na soja, a maior parte do K (60%) acumulado foi absorvida da camada superficial do solo, e nas plantas em sucessão a contribuição foi das camadas subsuperficiais, abaixo de 30 cm de profundidade (braquiária - 74%, milho-braquiária - 71% e milho - 81%). A recuperação do K reciclado da parte aérea da soja foi maior para a forrageira (84%), seguida pelo consórcio milho-braquiária (13%) e milho (2,5%). / This research was carried out to identify the soil depth from where K was absorbed and accumulated in the soybean (first season) and in the plants of succession (second season: corn, brachiaria and corn-brachiaria intercropped). In order to do so, it was used the rubidium element (Rb) as marker of potassium nutrient (K), which was positioned on the soil surface, 30 cm and 60 cm depths. The relative contribution of the soil layers to the K cycling will be assumed as the amount coming from the first 30 cm of soil (Rb at the surface), from 30 cm to 60 cm (Rb at 30 cm) and from 60 cm to 90 cm depth (Rb at 60 cm). Also, the cycling of K was obtained indirectly, from the recovery of Rb based on the hypothesis that it has equal recovery of K from the soil. The experiment was carried out at the Federal University of Goiás, Jataí Regional, in the season of 2015/2016. The experimental design was split-plot with randomized blocks and four replicates. The plots constitute the production systems (soybean, soybean/corn, soybean/brachiaria and soybean/corn-brachiaria intercropped), and the subplots correspond to the depths where the Rb was placed (soil surface, 30 and 60 cm deep). In soybean, most of the K uptake (60%) was taken from the soil surface layer, and in the plants in succession the contribution was from the subsurface layers, below 30 cm depth (brachiaria - 74%, Brachiaria-corn - 71% and corn - 81%). The recovery of recycled K of the soybean above ground was higher in the forage (84%), followed by the corn-brachiaria intercropped (13%) and corn (2.5%).
203

Automated test generation for production systems with a model-based testing approach / Génération de tests automatisés pour des systèmes de production avec une approche basée modèle

Durand, William 04 May 2016 (has links)
Ce manuscrit de thèse porte sur le problème du test basé modèle de systèmes de production existants, tels ceux de notre partenaire industriel Michelin, l’un des trois plus grands fabricants de pneumatiques au monde. Un système de production est composé d’un ensemble de machines de production contrôlées par un ou plusieurs logiciels au sein d’un atelier dans une usine. Malgré les nombreux travaux dans le domaine du test basé modèle, l’écriture de modèles permettant de décrire un système sous test ou sa spécification reste un problème récurrent, en partie à cause de la complexité d’une telle tâche. De plus, un modèle est utile lorsqu’il est à jour par rapport à ce qu’il décrit, ce qui implique de le maintenir dans le temps. Pour autant, conserver une documentation à jour reste compliqué puisqu’il faut souvent le faire manuellement. Dans notre contexte, il est important de souligner le fait qu’un système de production fonctionne en continu et ne doit être ni arrêté ni perturbé, ce qui limite l’usage des techniques de test classiques. Pour pallier le problème de l’écriture de modèles, nous proposons une approche pour construire automatiquement des modèles depuis des séquences d’événements observés (traces) dans un environnement de production. Pour se faire, nous utilisons les informations fournies par les données échangées entre les éléments qui composent un système de production. Nous adoptons une approche boîte noire et combinons les notions de système expert, inférence de modèles et machine learning, afin de créer des modèles comportementaux. Ces modèles inférés décrivent des comportements complets, enregistrés sur un système analysé. Ces modèles sont partiels, mais également très grands (en terme de taille), ce qui les rend difficilement utilisable par la suite. Nous proposons une technique de réduction spécifique à notre contexte qui conserve l’équivalence de traces entre les modèles de base et les modèles fortement réduits. Grâce à cela, ces modèles inférés deviennent intéressant pour la génération de documentation, la fouille de données, mais également le test. Nous proposons une méthode passive de test basé modèle pour répondre au problème du test de systèmes de production sans interférer sur leur bon fonctionnement. Cette technique permet d’identifier des différences entre deux systèmes de production et réutilise l’inférence de modèles décrite précédemment. Nous introduisons deux relations d’implantation : une relation basée sur l’inclusion de traces, et une seconde relation plus faible proposée, pour remédier au fait que les modèles inférés soient partiels. Enfin, ce manuscrit de thèse présente Autofunk, un framework modulaire pour l’inférence de modèles et le test de systèmes de production qui aggrège les notions mentionnées précédemment. Son implémentation en Java a été appliquée sur différentes applications et systèmes de production chez Michelin dont les résultats sont donnés dans ce manuscrit. Le prototype développé lors de la thèse a pour vocation de devenir un outil standard chez Michelin. / This thesis tackles the problem of testing (legacy) production systems such as those of our industrial partner Michelin, one of the three largest tire manufacturers in the world, by means of Model-based Testing. A production system is defined as a set of production machines controlled by a software, in a factory. Despite the large body of work within the field of Model-based Testing, a common issue remains the writing of models describing either the system under test or its specification. It is a tedious task that should be performed regularly in order to keep the models up to date (which is often also true for any documentation in the Industry). A second point to take into account is that production systems often run continuously and should not be disrupted, which limits the use of most of the existing classical testing techniques. We present an approach to infer exact models from traces, i.e. sequences of events observed in a production environment, to address the first issue. We leverage the data exchanged among the devices and software in a black-box perspective to construct behavioral models using different techniques such as expert systems, model inference, and machine learning. It results in large, yet partial, models gathering the behaviors recorded from a system under analysis. We introduce a context-specific algorithm to reduce such models in order to make them more usable while preserving trace equivalence between the original inferred models and the reduced ones. These models can serve different purposes, e.g., generating documentation, data mining, but also testing. To address the problem of testing production systems without disturbing them, this thesis introduces an offline passive Model-based Testing technique, allowing to detect differences between two production systems. This technique leverages the inferred models, and relies on two implementation relations: a slightly modified version of the existing trace preorder relation, and a weaker implementation proposed to overcome the partialness of the inferred models.Overall, the thesis presents Autofunk, a modular framework for model inference and testing of production systems, gathering the previous notions. Its Java implementation has been applied to different applications and production systems at Michelin, and this thesis gives results from different case studies. The prototype developed during this thesis should become a standard tool at Michelin.
204

The challenge of implementing TPS in the Czech Republic: A study in cross-cultural management / Výzva implementace TPS v České republice: studie v mezikulturním managementu

Koža, Michal January 2014 (has links)
This master's thesis analyzes the possibilities of implementation of Toyota Production System within Japanese subsidiaries in Czech Republic. It explores the fit between the cultural values of Czech and Japanese management and the values incorporated in the Toyota Production System. In order to conduct the study, 79 companies were contacted, and survey responses from a total of 108 Czech and Japanese employees were collected. Data from the survey show that both Czech and Japanese employees have similar values related to work and neither job satisfaction nor number of conflicts is connected with TPS training. In the conclusion, areas for further research and more detailed elaboration are identified and presented.
205

Um método para direcionar a implantação das ferramentas lean = uma aplicação numa empresa automotiva / A method to drive the implementation of lean tools : an application in an automotive industry

Nicodemo, Luiz Gustavo Grossi 18 August 2018 (has links)
Orientador: Paulo Corrêa Lima / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T11:47:36Z (GMT). No. of bitstreams: 1 Nicodemo_LuizGustavoGrossi_M.pdf: 2943348 bytes, checksum: 500fcfbed0c132f1e779eebf78bca027 (MD5) Previous issue date: 2005 / Resumo: Este trabalho apresenta uma metodologia para o direcionamento de projetos de melhoria nas empresas com base nas ferramentas do Sistema Toyota de Produção. Muito esforço têm sido despendido pelas empresas para alcançar resultados significativos em projetos de melhoria justamente pela não utilização de métodos estruturados de direcionamento destes projetos. O modelo metodológico proposto utiliza a integração entre o Mapa de Fluxo de Valor, o Balanced Scorecard, e o guia de produção enxuta da empresa como ferramenta para garantir a melhor relação possível entre custo e benefício alcançado nos projetos de melhoria. A validação do modelo se dá através de um projeto de implementação coordenado pelo autor, que utiliza esta metodologia durante mais de um ano em uma empresa de autopeças, e ao final do trabalho apresenta os ganhos referentes à aplicação do método / Abstract: This work presents a methodology to drive business improvement projects based on Toyota Production System tools. A lot of efforts are being spent by the companies to reach significant results on improvements projects because they do not utilize structured methods to drive these projects. The methodological model proposed uses the integration between the Value Stream Map, the Balanced Scorecard, and the Lean Production Guide of the company as a tool to assure the best possible relation between cost and reached benefits on improvements projects. The validation of the model occurs through an implementation project coordinated by the author, who applied this methodology for more than a year in an auto parts company and at the end presents the gains related to the application of the method / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
206

Návrh změn výrobního systému a inovací produktu pro zvýšení konkurenceschopnosti podniku / Proposal of Changes in the Production System and Product Innovations to Increase the Competitiveness of the Company

Fajkus, Marek January 2021 (has links)
The diploma thesis deals with the issue of increasing the competitiveness of the company with a focus on product and production. It compares theoretical knowledge, analyzes the current situation of the selected company, identifies the possibility of introducing innovation within the product portfolio and production system and proposes changes.
207

Analýza rizik výrobního systému / Production system risk analysis

Motyka, Pavel January 2010 (has links)
This thesis deals with risk assessment in the production system on the assembly line. Using risk analysis of each part of the production system will be realize the impact of the machinery to sevice. Then, by risk assessment often repetitive manual handling will be deal with the impact of the production system on health and safety service.
208

Analysis and improvement of material handling in a highly customized multi-variant product-based production system

Balasubramaniam, Arjun, Navuluri, Naga Lakshmana Naidu January 2020 (has links)
Twenty first century manufacturing is characterized by customer specific products. Customers expect greater differentiation in the products that companies offer to them, thus changing the whole landscape of production. Greater the variety of products being offered to customers, greater is the complexity of shop floor operations. This complexity is translated to all the operations in the shop floor including material handling and inventory control. To overcome this situation, many manufacturers have turned to “Lean Manufacturing” to gain a competitive edge in the market by reducing costs and improving productivity in all operations throughout the shop floor. Therefore, this purpose of this thesis is to analyze the material handling of a highly customized multi-variant product-based production system. The thesis represents a case study that was done at a caravan manufacturing company in Tenhult, Sweden. During the study, data was gathered from field notes, observations and multiple semi-structured interviews. The findings were analyzed with respect to a theoretical background which was generated through an extensive literature review that was carried out throughout the research. Our analysis was based on a systems approach where the findings were categorized into three dimensions that affect material handling and inventory control. These dimensions are warehouse management systems, culture, and production management, which contribute to successful implementation of lean into the material handling operations and inventory control. In conclusion, the results show that efficient material handling and inventory control can only be achieved by finding a synergy between technology, people and organization. Our results also show that soft issues like organizational culture and employee culture need to be addressed along with technological issues because only when an alignment between people, technology and business objectives and values is achieved, lean implementation can be successful. Our results also show the need for better supplier customer collaboration to reduce inventory levels and material handling operation.
209

Improvement of Value Stream Mapping and Internal Logistics through Digitalization: A study in the context of Industry 4.0

Sultan, Sahira, Khodabandehloo, Aida January 2020 (has links)
Traditional value stream mapping (VSM) is used to identify non-value-added (NVA) activities in lean production systems. However, VSM lacks flexibility and responsiveness due to its static nature, which limits its usage in complex and flexible production environments. Furthermore, in a production system, the internal logistics and production value streams are interconnected to each other. Therefore, they face the challenges of same nature such as poor material handling, lack of flexibility and lack of responsiveness. These challenges are disseminated from poor integration of internal logistics and production value streams. The lack of flexibility in VSM is discussed in previous research works to some extent but its lack of responsiveness has not received much attention. Similarly, poor material handling and lack of flexibility of internal logistics system are discussed extensively in previous research works; however, the lack of responsiveness of internal logistics has received very little attention. Furthermore, poor integration of internal logistics and production value streams has not received any attention in the previous research works. To overcome aforementioned challenges, this thesis emphasizes on combining digital technologies (e.g., RFIDs, sensors, barcodes, simulation and intelligent interfaces) with VSM and internal logistics system. However, there is very limited research that addresses improvement potentials in VSM and internal logistics system through digitalization. Therefore, this thesis aims to fill this gap by investigating the improvement potentials of digitalization for both value stream mapping and the internal logistics. In this regard, firstly the core challenges in value stream mapping and internal logistics system are identified. As a second step, possible improvement opportunities are identified in these two areas to increase the productivity of the production system through the adoption of digitalization. A qualitative research approach is performed in data collection methods such as observations and interviews. Furthermore, an empirical study is performed to provide an overview of the current production value streams and internal logistics system at a case company. The study concludes that the combination of VSM with simulation and real time data collection is vital to increase the flexibility and responsiveness of VSM. The improved flexibility and responsiveness of VSM will make it efficient to identify non-value-added activities. It is also discussed and demonstrated that the integration of internal logistics and production value streams can be improved through implementation of digital technologies such as AGVs, RFIDs/barcodes, IoT, data analytics and intelligent algorithms in the context of Industry 4.0. The improved integration of internal logistics and production value streams can improve the productivity of the production system to a large extent.
210

An Analysis of the Proactive Approach as a Potential Tool for Adaptability in Production Systems

Dencker, Kerstin January 2011 (has links)
Competitive systems for manufacturing, especially assembly systems, have to cope with frequent changes of external as well as internal demands. A proactive behaviour in an assembly system should make it capable of rapid changes and have an ability to handle frequent changes and disturbances. During recent decades several different system theories have occurred of which the majority remained theories never taken to actual production solutions. The thesis presents results from four case studies.   It is suggested, that the proactivity of an assembly system is strongly influenced by the system’s ability to change the three parameters: 1) level of automation, 2) level of information, 3) level of competence[l3]  (among the operators in a defined work area).   Proactivity is not easy to describe. However, this[l4]  thesis has taken a step in that direction. A general definition of proactivity is “taking action by causing change towards a state and not only reacting to change when it happens”. Another way to phrase this is "to be anticipatory and taking charge of situations”. Proactivity can be described as the ability of preparation for: - Changes and disturbance during operation; - Planned long-term evolution for a sustainable and perfect production system.   Such a system consists of technical components efficiently integrated with human operators and has the ability to handle frequent changes. Proactivity in an assembly system is dependent on the following factors: -         Continuous changes; -         Mandate to allocate resources; -         Mandate to do short term planning. The thesis presents a first model for evaluation of different technical resources that contributes to an overall proactive system behaviour. The model has been published but not yet tested. / QC 20120119

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