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No / The regulation of linearized multivariable system models, following input set point and load disturbance changes, is considered. An inner and outer closed-loop control strategy is outlined, enabling targeted recovery rates, offset attenuation and low steady state interaction to be achieved. Proportional control and passive network compensation alone are employed. Gain ratio selection and outer loop tuning are exercised, ensuring thereby the confinement of output perturbations to low-frequency load disturbances and reference input changes. Application studies are presented for purposes of comparison.

Cycle-to-cycle control is a method for using feedback to improve product quality for processes that are inaccessible within a single processing cycle. This limitation stems from the impossibility or the prohibitively high cost of placing sensors and actuators that could facilitate control during, or within, the process cycle. Our previous work introduced cycle to cycle control for single input-single output systems, and here it is extended to multiple input-multiple output systems. Gain selection, stability, and process noise amplification results are developed and compared with those obtained by previous researchers, showing good agreement. The limitation of imperfect knowledge of the plant model is then imposed. This is consistent with manufacturing environments where the cost and number of tests to determine a valid process model is desired to be minimal. The implications of this limitation are modes of response that are hidden from the controller. Their effects on system performance and stability are discussed. / Singapore-MIT Alliance (SMA)

The multivariable Alexander polynomial (MVA) is a classical invariant of knots and links. We give an extension to regular virtual knots which has simple versions of many of the relations known to hold for the classical invariant. By following the previous proofs that the MVA is of finite type we give a new definition for its weight system which can be computed as the determinant of a matrix created from local information. This is an improvement on previous definitions as it is directly computable (not defined recursively) and is computable in polynomial time. We also show that our extension to virtual knots is a finite type invariant of virtual knots. We further explore how the multivariable Alexander polynomial takes local information and packages it together to form a global knot invariant, which leads us to an extension to tangles. To define this invariant we use so-called circuit algebras, an extension of planar algebras which are the `right' setting to discuss virtual knots. Our tangle invariant is a circuit algebra morphism, and so behaves well under tangle operations and gives yet another definition for the Alexander polynomial. The MVA and the single variable Alexander polynomial are known to satisfy a number of relations, each of which has a proof relying on different approaches and techniques. Using our invariant we can give simple computational proofs of many of these relations, as well as an alternate proof that the MVA and our virtual extension are of finite type.

The multivariable Alexander polynomial (MVA) is a classical invariant of knots and links. We give an extension to regular virtual knots which has simple versions of many of the relations known to hold for the classical invariant. By following the previous proofs that the MVA is of finite type we give a new definition for its weight system which can be computed as the determinant of a matrix created from local information. This is an improvement on previous definitions as it is directly computable (not defined recursively) and is computable in polynomial time. We also show that our extension to virtual knots is a finite type invariant of virtual knots. We further explore how the multivariable Alexander polynomial takes local information and packages it together to form a global knot invariant, which leads us to an extension to tangles. To define this invariant we use so-called circuit algebras, an extension of planar algebras which are the `right' setting to discuss virtual knots. Our tangle invariant is a circuit algebra morphism, and so behaves well under tangle operations and gives yet another definition for the Alexander polynomial. The MVA and the single variable Alexander polynomial are known to satisfy a number of relations, each of which has a proof relying on different approaches and techniques. Using our invariant we can give simple computational proofs of many of these relations, as well as an alternate proof that the MVA and our virtual extension are of finite type.

In this work, two different problems are addressed. In the first part, the problem of synthesizing a set of stabilizing controllers for unknown multivariable systems using direct data is analyzed. This is a model free approach to control design and uses only the frequency domain data of the system. It is a perfect complement to modern and post modern methods that begin the control design with a system model. A three step method, involving sequential design, search for stability boundaries and stability check is proposed. It is shown through examples that a complete set of stabilizing controllers of the chosen form can be obtained for the class of linear stable multivariable systems. The complexity of the proposed method is invariant with respect to the order of the system and increases with the increase in the number of input channels of the given multivariable system. The second part of the work deals with the problem of identification of model uncertainties and the effect of unwanted exogenous inputs acting on a discrete time multivariable system using its output information. A disturbance model is introduced which accounts for the system model uncertainties and the effect of unwanted exogenous inputs acting on the system. The frequency content of the exogenous signals is assumed to be known. A linear dynamical model of the disturbance is assumed with an input that has the same frequency content as that of the exogenous input signal. The extended model of the system is then subjected to Kalman filtering and the disturbance states estimates are used to obtain a least squares estimate of the disturbance model parameters. The proposed approach is applied to a linear multivariable system perturbed by an exogenous signal of known frequency content and the results obtained depict the efficacy of the proposed approach.

Les travaux présentés dans ce manuscrit s’inscrivent dans le cadre du développement de la commande robuste de l’équipe CRONE (Commande Robuste d’Ordre Non Entier). Ils portent plus précisement sur le développement d’une méthodologie de synthèse de la commande CRONE pour les systèmes multivariables avec une application au contrôle des moteurs à combustion interne. Après un chapitre d’introduction sur la commande robuste d’ordre non entier dans le but de garantir une robustesse des performances dynamiques par rapport aux variations des paramètres du modèle du système, une reformulation des conditions de stabilité de la méthodologie CRONE des systèmes multivariables (MIMO) carrées existante est proposée. Un ensemble de théorèmes est aussi proposé afin de pouvoir étendre la commande CRONE des systèmes MIMO carrés au cas plus général des systèmes multivariables ayant des retards purs et un comportement oscillatoire avec des pôles et des zéros qui ne sont pas nécessairement situés dans le domaine de stabilité. Le chapitre 3 de ce manuscrit est consacré d’une part à la commande des systèmes MIMO non-carrés (nombre d’entrées différent de celui des sorties), instables et à non-minimum de phase et d’autre part a la simplification des différentes méthodologies de commande proposées dans ce manuscrit. Cette simplification est basée sur une analyse des effets de couplage du système et sur l’hypotheses que dans certain cas des éléments de la matrice de transfert du système peuvent être considérés comme des incertitudes lors de l’optimisation de la boucle ouverte nominale non entiere. Outre un ensemble de cas académique pris dans la littérature, la validation de ces travaux est réalisée à travers la commande du système d'air de deux moteurs à combustion interne : un moteur à essence avec une loi de commande CRONE MIMO carrée ; un moteur diesel avec une loi de commande CRONE MIMO non carrée. Le but fixé par l'industriel à l'origine de ces applications est d’optimiser le compromis performances-pollution-consommation de ces moteurs tout en minimisant les efforts liés à la conception de ces nouvelles lois de commande. / The works presented in this thesis are led within the framework of robust control developments of the CRONE team (Robust Control of fractional order). They are carried more precisely on the development of a synthesis methodology of the CRONE control for multivariable systems with an application of controlling internal combustion engine. After an introductive chapter on the robust control of fractional order with a view to garanty dynamic performance robustness compared with parameter uncertainties of the system model, another stability condition formulation of the CRONE methodology for multivariable square systems is put forward. A set of theorems is also offered in order to extend the square MIMO system CRONE control to the most general case of multivariable systems having delays and oscillatory behaviours with zeros and poles that are not necessarily on the stability domain. Chapter 3 is devoted on one hand to the control of non square (number of entries differents from the output number), instable and non minimal phase MIMO systems and on the other hand on the simplification of different control methodologies detailed in this thesis. This simplification is based on the analysis of system coupling effects and under the assumptions that in some cases, elements of the system transfer matrix can be considered as uncertainties when optimizing the fractional nominal open loop. Beyond a set of academic cases out of the literature, the validation of these works is achieved through the control of the air intake of two internal combustion engines : a gasoline engine with a square CRONE MIMO control ; a diesel engine with a non square CRONE MIMO control. The aim specified by the industrial is to optimize the compromise between performances-pollution-consumption of these engines.

A southern Mississippi broiler complex in an area of high poultry density experienced persistent lower livability and growth performance compared with company averages for the state. It was hypothesized that circulating Infectious Bronchitis Virus (IBV) challenge exacerbated by underlying Infectious Bursal Disease (IBD)-induced immune suppression was the primary contributor to reduced livability and live production performance on certain farms, and that disease challenges were most prevalent on farms in areas of high bird density. A retrospective analysis of data from a three-year period (March 2014 through March 2017) was designed to investigate the role of disease, settlement, geographic, and weather variables in broiler mortality. A database comprising diagnostic variables (processing-age ELISA titers for Infectious Bursal Disease (IBD), Infectious Bronchitis Virus (IBV), Newcastle Disease Virus (NDV), and Reovirus (REO)), settlement variables (downtime, age at processing, average weight at processing, week 1 mortality, genetic line, year, and broiler vaccination programs), geographic variables (number of commercial chicken farms and houses within 1 km, 5 km, 10 km and 15 km radii), and weather variables (average temperature, average heat index, and average humidity for the first 7 days and last 14 days of grow-out) was created and analyzed using univariable and multivariable statistical analyses. First-week mortality, processing age, average processing weight, genetic line, NDV/IBV vaccination program, and heat index in the last 14 days of the grow-out period were found to be significantly associated with flock mortality in this broiler complex (P <= 0.05). The results of this study should guide future management and disease control strategies aimed at reducing broiler mortality. Future studies with more diagnostic data are needed to further investigate the relative contribution of diseases to broiler flock mortality.

No description available.

Esta tesis comprende el desarrollo e implementación de nuevas metodologías de control estadístico multivariable (MSPC), su aplicación para monitorear la producción de procesos de polimerización en emulsión discontinuos (batch) y la comparación del desempeño de diferentes estrategias dedicadas al monitoreo estadístico de procesos batch. Los procesos de polimerización presentan características que los hacen atractivos como casos de estudio para evaluar las técnicas de MSPC. Dada la complejidad de estos sistemas, y la gran cantidad de fuentes de variación que los afectan, la implementación de técnicas de monitoreo y control basadas en datos resulta una alternativa atractiva y realizable. Los procedimientos de MSPC se componen de tres etapas fundamentales: detección, identificación y diagnosis. El estado del sistema se monitorea en forma continua para evaluar si el mismo se encuentra operando en condiciones normales. Si se detecta un evento anormal, resulta necesario identificar las variables que señalan esta condición y luego diagnosticar la causa primera de la anomalía. Los estudios y desarrollos de esta tesis comprenden a las etapas de detección e identificación de fallas. Se desarrolló una nueva metodología, denominada OSS (Original Space Strategy), para la descomposición del estadístico de Hotelling en el espacio de las mediciones, que permite evaluar la influencia que tiene cada variable en el valor de dicho estadístico. Las principales ventajas de la estrategia de identificación propuesta son las siguientes: permite monitorear el proceso usando un sólo estadístico, reduce significativamente las ambigüedades en la identificación de fallas propias de otras técnicas existentes, evita la posible pérdida de información originada por la proyección de los datos en un espacio de variables latentes de dimensión incorrecta, proporciona una clara comprensión del significado físico de las contribuciones negativas al estadístico y determina un valor límite para las mismas. Se propone la incorporación de la metodología OSS como herramienta de identificación en el nuevo procedimiento de monitoreo de procesos batch propuesto. En esta tesis se analizaron en detalle los métodos más utilizados para el monitoreo de procesos batch. Los mismos se basan en técnicas de proyección tales como el Análisis de Componentes Principales (PCA) y el Análisis de Componentes Independientes (ICA). Se comparó el desempeño de estas estrategias con la propuesta en esta tesis, mediante su aplicación a un reactor de polimerización. El conjunto de datos analizados se obtuvo por simulación usando un modelo riguroso de un reactor de polimerización en emulsión de metacrilato de metilo. La comparación del desempeño se basó en los resultados obtenidos mediante la aplicación de los procedimientos a una serie de fallas conocidas. Los mismos se compararon en términos de: la capacidad de cada técnica para detectar la existencia de la falla y la exactitud con la que la metodología indica las variables sospechosas durante la etapa de identificación. Los resultados de la aplicación de la estrategia propuesta, caracterizada por utilizar un solo estadístico, a este complejo caso de estudio muestran un muy buen desempeño de la misma, en lo referente a su velocidad de detección y exactitud en la identificación, cuando se lo compara con el obtenido usando PCA o ICA. / This thesis involves the development and implementation of new methodologies for Multivariate Statistical Process Control (MSPC), their application to monitor the production of batch emulsion polymerization processes and the performance comparison among different techniques devoted to the statistical monitoring of batch processes. Polymerization processes have distinctive features that make them attractive as case studies to evaluate MSPC techniques. Due to the inherent complexity of these systems and the huge amount of variation sources that affect them, the implementation of data-driven monitoring and control techniques arises as an attractive and feasible alternative. The MSPC procedures are made up of three essential stages: detection, identification and diagnosis. The process state is evaluated continuously to determine if its operation is normal. If an abnormal event is detected, it is necessary to identify the variables that signal this condition, and then to diagnosis the first source of the anomaly. The studies and developments of this thesis involve the fault detection and identification stages. A new methodology, called OSS (Original Space Strategy), is developed to decompose the Hotellings statistic that allows evaluating the influence of each variable on the statistic value. The main advantages of the proposed identification strategy are: process monitoring is accomplished using only one statistic, it significantly reduces the ambiguities in fault identification inherent to other existing techniques, it avoids the possible loss of information that may arise when data are projected into a latent variable space of inappropriate dimension, it provides a clear understanding of the physical meaning of negative contribution to the statistic value and determines a limit for them. It should be highlighted the incorporation of the OSS methodology as identification tool for the new proposed monitoring procedure. In this thesis the most used methods for batch process monitoring are analyzed in detail. They are based on projection techniques, such as, Principal Component Analysis (PCA) and Independent Component Analysis (ICA). A performance comparison is conducted among these strategies and the proposed one for their application to a polymerization reactor. The data set was obtained by simulation using a rigorous model of an emulsion polymerization reactor for the production of methylmetacrylate. The performance comparison is based on the results obtained from the application of the procedures to a set of known faults. They are compared in terms of the capacity of each technique to detect the existing faults and the accuracy of the methodology to indicate the suspicious variables during the identification stage. The application results of the proposed strategy, which is characterized by the use of only one statistic, to this complex case study show that it has a good performance regarding its detection velocity and identification accuracy, in comparison with methods base on PCA o ICA.