A operação de adubação responde por parte significativa dos custos de produção agrícola. Melhorar a qualidade dessa operação acarreta benefícios econômicos e ambientais. O processo de adubação normalmente é realizado a uma taxa média, representativa de uma área, no entanto, propriedades químicas do solo podem variar consideravelmente dentro dessa área. Desse modo, alguns locais poderão receber fertilizantes e/ou corretivos em excesso, enquanto outros poderão receber quantidades insuficientes. A alternativa à taxa média é a realizar a aplicação à taxa variada, que se caracteriza por aplicar os insumos de acordo com as necessidades específicas dentro da área. Para que essa aplicação aconteça, mecanismos dosadores controlam a aplicação. O objetivo deste estudo é avaliar os mecanismos dosadores de uma carreta adubadora de arrasto, comportas e esteiras, atendem as prescrições de doses previstas no mapa de recomendação de adubação. Para avaliar a uniformidade da operação utilizou-se o controle estatístico do processo. De acordo com os resultados obtidos pode-se afirmar que os mecanismos dosadores não atenderam a condição de realizar a aplicação à taxa variável de maneira uniforme. / The operation fertilization accounts for a significant portion of the costs of agricultural production. Improve the quality of this operation entails economic and environmental benefits. The process of fertilization is usually performed at an average rate representative of an area, however, the chemical properties of soil can vary considerably within the area. Thus, some locations may receive fertilizer and / or lime in excess, while others may receive insufficient amounts. The alternative is to average the application to perform variable rate, characterized by applying inputs according to the specific requirements within the area. For this application happens, metering mechanisms control the application. The aim of this study is to evaluate the dosing mechanisms of a truck hauling fertilizer, locks and mats, meet the requirements of the prescribed dose map fertilizer recommendation. To evaluate the uniformity of operation used the statistical process control. According to the obtained results it can be stated that the meter mechanism did not meet the condition to perform variable rate application to uniformly.

Com o aumento da produção mundial em proporções cada vez maiores, os processos industriais têm se tornando um desafio pela complexidade do seu gerenciamento. A identificação rápida e precisa de não conformidades é cada vez mais necessária e mais difícil de ser realizada. Este estudo propõe a integração do Controle de Engenharia com o Controle Estatístico de Processo, no monitoramento e controle de processos industriais, almejando a percepção mais rápida de anormalidades, visando à redução de problemas de especificação de produtos. Uma forma de autoajuste do controlador Proporcional-Integral e Derivativo (PID) é proposta, aumentando a robustez do sistema, empregando-se técnicas comumente utilizadas nos processos. O modelo matemático do processo, equacionando as relações das variáveis envolvidas, é estabelecido para determinação e especificação do controlador e de forma conjunta as cartas de controle são configuradas. O controlador projetado para a situação normal de operação atua no sentido de manter as variáveis de saída (controladas) dentro de especificações através do conhecimento de sua relação com as de entrada e de processo. As cartas de controle baseadas em modelos, monitorando os resíduos provenientes de ajustes de modelos ARIMA, acompanham as variações do processo, evitando variabilidade excessiva e possibilitando a detecção de comportamentos anormais, inclusive monitorando o desempenho do próprio controlador. Com a sinalização das cartas de controle, é realizada uma interferência na equação de ajuste do controlador. Empregando-se a simulação numérica, analisam-se os comportamentos do controlador e este, combinado com as cartas de controle. Falhas inseridas propositalmente, em cada variável controlada, foram devidamente sinalizadas. Estas sinalizações ocorreram mesmo em situações em que as variáveis estiveram mantidas dentro da especificação pelo controlador. Para o sistema de autoajuste, o aumento dos ganhos de contribuição das cartas de controle proporcionou maior acurácia das variáveis controladas (monitoradas). A integração proposta apresentou melhores resultados, quanto à manutenção das variáveis de saída próximas aos seus alvos, quando comparada com o controlador operando isoladamente. / With the increase of world production at bigger and bigger proportions, the industrial processes have become a challenge by the complexity of their management. The fast and precise identification of non-conformities is increasingly necessary and more difficult to be performed, preferably even before problems with product specification or waste can be considered. This study proposes the integration of Engineering Process Control with the Statistical Process Control, in monitoring and controlling of industrial processes, aiming the quicker perception of abnormalities, looking for the reduction of products specification problems. A form of self-adjustment of the Proportional-Integral and Derivative Controller (PID) is proposed, increasing the system robustness applying techniques commonly used in the processes. The mathematical model of the process, equating the relationship of the variables involved, is established to the determination and specification of the controller, and the control charts are configure in an integrated way. The controller projected to the normal operation situation, acts in the sense of keeping the exit variables (controlled) within the specifications through the knowledge of its relationship with that of the entrance and that of the process. The control charts based in models, monitoring the residues coming from the models adjustment ARIMA, follow up the process variations avoiding excessive variability and making it possible the detection of abnormal behaviors, even monitoring the performance of the controller itself. With the signalling of the control charts, an interference in the equation of adjustment of the controller is performed. Applying the numerical simulation, the controller behaviors are analyzed and this combined with the control charts. Intentionally inserted failures, in each controlled variable, were properly signalized. These signallings have happened even in situations where the variables were kept by the controller within the specification.. To the self-adjustment system, the increase of contribution gains of the control charts has provided greater accuracy of the controlled variables. The integration proposed has presented better results, in relation to maintain of the exit variables next to their targets, when compared to the controller operating in isolation.

A incerteza de medição ainda é tema de estudo e desenvolvimento, mesmo quase vinte anos após o lançamento do ISO GUM, que definiu um padrão internacional para o cálculo de incerteza. Mesmo assim, poucos estudos tratam da interface entre a incerteza de medição e outros aspectos da qualidade industrial, em especial ferramentas de controle de processo como cartas de controle. Assim, o objetivo deste trabalho é estudar os efeitos da incerteza em cartas de controle e identificar sob quais situações de aplicação ela exerce maior influência. Foi feito um mapeamento dos artigos publicados entre 2004 e 2010 sobre incerteza de medição, para identificar quais as metodologias de cálculo e abordagem são mais utilizadas. Na sequência, foi desenvolvido um método incluir nas cartas de controle a incerteza do sistema de medição, modificando as probabilidades de erros tipo I e tipo II. Finalmente, foi elaborada uma simulação computacional utilizando o método desenvolvido, para que fosse possível analisar quais as situações nas quais a incerteza de medição deve ser obrigatoriamente considerada e quais ela pode ser negligenciada. / The measurement uncertainty is still subject of study and development, even almost twenty years after the release of the ISO GUM, which set an international standard for the its calculation. Still, few studies have addressed the interface between the measurement uncertainty and other aspects of industrial quality, in particular process control tools like control charts. The objective of this work is to study the effects of measurement uncertainty on control charts and to identify the situations in which its application exerts greater influence. A research was made, mapping of the articles published between 2004 and 2010 regarding measurement uncertainty, aiming to identify which calculation methods and approaches are most widely used. After, a method was developed to include uncertainty of the measurement system in control charts, modifying the probabilities of type I and type II errors. Finally, it was created a computer simulation using the method developed, to make it possible to analyze those situations in which the measurement uncertainty must be considered and which it can be neglected.

Orientadores: André Franceschi de Angelis, Laura Letícia Ramos Rifo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-20T08:56:00Z (GMT). No. of bitstreams: 1 Spagnol_RenataLussier_M.pdf: 2580788 bytes, checksum: a72f66f9e14fea6b229299437558a1ed (MD5) Previous issue date: 2011 / Resumo: A sociedade atual é dependente das Redes de Computadores para seu cotidiano e, portanto, mantê-las em boas condições de operação é essencial. Reagir aos problemas é uma estratégia que implica em degradação ou interrupção da rede e incorre geralmente em altos custos. é preferível detectar antecipadamente os problemas e corrigi-los proativamente, o que implica no uso de técnicas preditivas para controle, tais como os métodos estatísticos. Este trabalho determinou a possibilidade de se avaliar a rede com um menor número de variáveis em relação a um modelo existente e apontou maneiras de aprimorar a qualidade do monitoramento com uso técnicas estatísticas mais recentes e menos usuais. Os experimentos realizados consistiram-se na análise de traços de uma rede real previamente armazenados em bases de dados, sobre os quais foram aplicados cálculos de coeficiente de correlação linear para redução de variáveis. Ajustou-se um modelo para a rede com métodos de análises de Séries Temporais e foram testadas as cartas de Soma Acumulativa (CUSUM) e de Média Móvel Exponencialmente Ponderada (MMEP) em substituição às de média e amplitude. Obteve-se uma redução inicial de 23 para 4 na quantidade de variáveis a monitorar estatisticamente, com possibilidade de se chegar a uma única medida, simplificando os processos de controle da rede. Foi possível ajustar um Modelo Autoregressivo Integrado Média Móvel (ARIMA) para a rede e monitorá-la através de cartas CUSUM e MMEP, demonstrando-se a última mais adequada ao problema / Abstract: The nowadays society depends on computer networks for its daily activities and, therefore, it is essential to keep them in good operation conditions. React to the problems is a strategy that implies the network degradation or its interruption and increases maintenance costs. It is preferable the early detection of the problems and its proactive correction. This approach implies in the use of control prediction techniques, as stochastic methods. The present work has showed that the use of recent and less common statistics techniques can enhance the monitoring quality of the networks with fewer variables than a previous model. The linear correlation coefficient method was employed for the reduction of the number of variables over previously data base stored network traces. It was performed a model adjustment for the network using the temporal series method. The Cumulative Sum control chart (CUSUM) and the Exponentially Weighted Moving Average (EWMA) were used in replacement of common charts of average and range. It was obtained an initial reduction from 23 to 4 in the statistical monitored variables and it is possible to reach only one measure in some conditions, simplifying the network control process. It was possible to adjust an Autoregressive Integrated Moving Average (ARIMA) to the network and monitor it through CUSUM and EWMA. The last one was demonstrated to be the most suitable to the problem / Mestrado / Tecnologia e Inovação / Mestre em Tecnologia

Fault detection and diagnosis is an important problem in process engineering. In this dissertation, use of multivariate techniques for fault detection and diagnosis is explored in the context of statistical process control. Principal component analysis and its extension, kernel principal component analysis, are proposed to extract features from process data. Kernel based methods have the ability to model nonlinear processes by forming higher dimensional representations of the data. Discriminant methods can be used to extend on feature extraction methods by increasing the isolation between different faults. This is shown to aid fault diagnosis. Linear and kernel discriminant analysis are proposed as fault diagnosis methods. Data from a pilot scale distillation column were used to explore the performance of the techniques. The models were trained with normal and faulty operating data. The models were tested with unseen and/or novel fault data. All the techniques demonstrated at least some fault detection and diagnosis ability. Linear PCA was particularly successful. This was mainly due to the ease of the training and the ability to relate the scores back to the input data. The attributes of these multivariate statistical techniques were compared to the goals of statistical process control and the desirable attributes of fault detection and diagnosis systems. / Dissertation (MEng (Control Engineering))--University of Pretoria, 2008. / Chemical Engineering / MEng / Unrestricted

Motivés par des besoins en industrie microélectronique, ces travaux apportent des contributions en modélisation probabiliste de données spatiales, et en maîtrise statistique de procédés.Le problème spatial a pour spécificité d’être posé sur un domaine circulaire. Il se représente par un modèle de krigeage dont la partie déterministe est constituée de polynômes orthogonaux et la partie stochastique de processus gaussiens. Traditionnellement définis avec la norme euclidienne et la mesure uniforme sur le disque, ces choix n’exploitent pas les informations a priori sur les procédés d’usinage.Pour tenir compte des mécanismes de rotation ou de diffusion à partir du centre, nous formalisons les processus gaussiens polaires sur le disque. Ces processus intègrent les corrélations radiales et angulaires dans le modèle de krigeage, et en améliorent les performances dans les situations considérées. Ils sont ensuite interprétés par décomposition de Sobol et généralisés en dimension supérieure. Des plans d’expériences sont proposés dans le cadre de leur utilisation. Au premier rang figurent les cylindres latins qui reproduisent en coordonnées polaires les caractéristiques des hypercubes latins.Pour intégrer à la fois les aspects spatiaux et temporels du problème industriel, la maîtrise statistique de procédé est abordée en termes d’application de cartes de contrôle aux paramètres des modèles spatiaux. Les séries temporelles suivies ont aussi la particularité de comporter des données atypiques et des changements structurels, sources de biais en prévision, et de fausses alarmes en suivi de risque. Ce problème est traité par lissage robuste et adaptatif. / Driven by industrial needs in microelectronics, this thesis is focused on probabilistic models for spatial data and Statistical Process Control. The spatial problem has the specificity of being defined on circular domains. It is addressed through a Kriging model where the deterministic part is made of orthogonal polynomials and the stochastic term represented by a Gaussian process. Defined with the Euclidean distance and the uniform measure over the disk, traditional Kriging models do not exploit knowledge on manufacturing processes. To take rotations or diffusions from the center into account, we introduce polar Gaussian processes over the disk. They embed radial and angular correlations in Kriging predictions, leading to significant improvements in the considered situations. Polar Gaussian processes are then interpreted via Sobol decomposition and generalized in higher dimensions. Different designs of experiments are developed for the proposed models. Among them, Latin cylinders reproduce in the space of polar coordinates the properties of Latin hypercubes. To model spatial and temporal data, Statistical Process Control is addressed by monitoring Kriging parameters, based on standard control charts. Furthermore, the monitored time – series contain outliers and structural changes, which cause bias in prediction and false alarms in risk management. These issues are simultaneously tackled with a robust and adaptive smoothing.

The thesis is concerned with the aplication of the statistical process control on the new product and it provides proposals to its improvement in Plastik, s.r.o.

The broader research area investigated during this programme was conceived from a goal to contribute towards solving the challenge of food security in the 21st century through the reduction of crop loss and minimisation of fungicide use. This is aimed to be achieved through the introduction of an empirical approach to agricultural disease monitoring. In line with this, the SYIELD project, initiated by a consortium involving University of Manchester and Syngenta, among others, proposed a novel biosensor design that can electrochemically detect viable airborne pathogens by exploiting the biology of plant-pathogen interaction. This approach offers improvement on the inefficient and largely experimental methods currently used. Within this context, this PhD focused on the adoption of multidisciplinary methods to address three key objectives that are central to the success of the SYIELD project: local spore ingress near canopies, the evaluation of a suitable model that can describe spore transport, and multivariate analysis of the potential monitoring network built from these biosensors. The local transport of spores was first investigated by carrying out a field trial experiment at Rothamsted Research UK in order to investigate spore ingress in OSR canopies, generate reliable data for testing the prototype biosensor, and evaluate a trajectory model. During the experiment, spores were air-sampled and quantified using established manual detection methods. Results showed that the manual methods, such as colourimetric detection are more sensitive than the proposed biosensor, suggesting the proxy measurement mechanism used by the biosensor may not be reliable in live deployments where spores are likely to be contaminated by impurities and other inhibitors of oxalic acid production. Spores quantified using the more reliable quantitative Polymerase Chain Reaction proved informative and provided novel of data of high experimental value. The dispersal of this data was found to fit a power decay law, a finding that is consistent with experiments in other crops. In the second area investigated, a 3D backward Lagrangian Stochastic model was parameterised and evaluated with the field trial data. The bLS model, parameterised with Monin-Obukhov Similarity Theory (MOST) variables showed good agreement with experimental data and compared favourably in terms of performance statistics with a recent application of an LS model in a maize canopy. Results obtained from the model were found to be more accurate above the canopy than below it. This was attributed to a higher error during initialisation of release velocities below the canopy. Overall, the bLS model performed well and demonstrated suitability for adoption in estimating above-canopy spore concentration profiles which can further be used for designing efficient deployment strategies. The final area of focus was the monitoring of a potential biosensor network. A novel framework based on Multivariate Statistical Process Control concepts was proposed and applied to data from a pollution-monitoring network. The main limitation of traditional MSPC in spatial data applications was identified as a lack of spatial awareness by the PCA model when considering correlation breakdowns caused by an incoming erroneous observation. This resulted in misclassification of healthy measurements as erroneous. The proposed Kriging-augmented MSPC approach was able to incorporate this capability and significantly reduce the number of false alarms.

Due to growing awareness of sustainable development and renewable sources of electricity, the public demand for electric cars has increased during the last decade, Lithium-ion batteries are used to power today's electric cars and the batteries are mainly produced in Asia. The need for batteries in the automobile industry in Europe has led to the birth of many new organisations, Northvolt is one of them. The mission at Northvolt is to bring lithium-ion batteries to the European market. The process of producing Lithium-ion batteries is complex and includes several sub-processes that together will generate the final product. The quality of the processes and product are important for performance as well as safety. Statistical Process Control is one way of creating and maintaining good quality. This thesis aims to describe how Statistical Process Control can be implemented in the context of Lithium-ion battery production. To answer the aim, a literature study and a field study were conducted at Northvolt labs in Västerås. The field study collected data through interviews, as well as observations on the different processes in production. A thematic analysis was conducted, the findings resulted in a framework for implementation of Statistical Process Control in the Lithium-ion battery industry. The framework has similarities with other frameworks gathered from literature on Statistical Process Control implementation but differs in some key aspects. A clear emphasis on initial focus regarding training and education is one aspect that contributes to the existing literature and a practical contribution to organisations in the batter production industry. Early focus on process definition and identification of critical-to-quality characteristics are also aspects that are emphasised in the developed framework. The emphasize on these factors are connected to the complexity of the processes of the Lithium-ion battery production.

The presented thesis deals with the issue of statistical quality control of a specific production process. The thesis presents a range of statistical tools that can be used to identify the factors causing a high proportion of non-standard pieces. The diploma thesis practically introduces the application of these quality management tools to the production process characterized by an increased proportion of non-standard pieces, in which the factors causing their occurrence are unknown, and as following the thesis in detail introduces the approach how to detect these factors. The last part of the work summarizes the recommendations handed over to the company in order to verify the conclusions of the thesis.