IEEE Transactions on Control Systems Technology, 2020
This paper is focused on closed-loop control of postprandial glucose levels of patients with type... more This paper is focused on closed-loop control of postprandial glucose levels of patients with type 1 diabetes mellitus after unannounced meals, still a major challenge towards a fully autonomous artificial pancreas. The main limitations are the delays introduced by the subcutaneous insulin pharmacokinetics and the glucose sensor, which typically lead to insulin over-delivery. Current solutions reported in the literature typically resort to meal announcement, which requires the patient intervention. In this paper, a disturbance observer is used to estimate the effect of unannounced meals and the insulin pharmacokinetics is taken into account by means of a feedforward compensator. The proposed strategy is validated in silico with the UVa/Padova metabolic simulator. It is demonstrated how the disturbance observer successfully estimates and counteracts not only the effect of meals but also sudden drops in the glucose levels that may lead to hypoglycemia. For unannounced meals, results show a median time-in-range of 80% in a 30-day scenario with high carbohydrate content and large intra-subject variability. Optionally, users may decide to announce meals. In this case, considering severe bolus mismatch due to carbohydrate counting errors, the median time-in-range is increased up to 88%. In every case, hypoglycemia is avoided.
A valuable option in complex systems modelling is the use of fuzzy models, but fuzzy modelling sh... more A valuable option in complex systems modelling is the use of fuzzy models, but fuzzy modelling should have interpretability of the obtained models as a fundamental goal. Additionally, some considerations must be taken into account when subsequent use of this models is local model control, provided that it might influence the criteria used in identification for prediction. In this Thesis, after elucidating some unclear concepts found in literature regarding local modelling criteria, desirable characteristics of fuzzy modelling and identification techniques for control purposes are proposed. Behaviuor of objective functions of local-model-control-oriented fuzzy clustering algorithms is studied and a new index is presented so that it incorporates some desirable characteristics regarding convexity and smoothness of the final identified clusters, with advantages regarding other methodologies such as Gustaffson-Kessel. Subsequently, the definition of a family of clustering algorithms for previously defined objective function minimization is done. They lead to a better identification of local models approximating the linearized plant model on their validity zones and with some additional desirable characteristics regarding membership function interpretability (convexity and smoothness). The algorithm simultaneously provided local linear models and input clustering, being specially suitable for Takagi-Sugeno fuzzy models identification and local linear models decomposition of nonlinear systems for control. ix x
A Fick's model that includes a Takagi-Sugeno fuzzy model to estimate the effective diffusivity wa... more A Fick's model that includes a Takagi-Sugeno fuzzy model to estimate the effective diffusivity was analyzed. The modelling of drying kinetics on mango trough this diffusional-fuzzy model was compared with the theoretical Fick's model and the empirical Peleg and Weibull models. The identification and validation was performed from experimental drying curves of ripe mango slices (Mangifera indica L. cv. Tommy Atkins) at constant air velocity (4 m/s) and different drying temperatures (40, 50, 60 and 70 ºC). The fuzzy sets for the antecedent of Takagi-Sugeno system were identified by the Gustafson-Kessel clustering algorithm and approximated by membership functions of piecewise exponential form. On identification and validation, the diffusional-fuzzy model showed best results than the Fick's model, whereas it showed little difference with the Weibull and Peleg models. The diffusional-fuzzy model keeps the interpretability of Fick's model, improves the process simulation and avoids phenomenon and property considerations which require additional experimental and modelling work.
This paper presents an alternative inference-defuzzification algorithm for Takagi-Sugeno fuzzy sy... more This paper presents an alternative inference-defuzzification algorithm for Takagi-Sugeno fuzzy systems that preserves local-model interpretation and convexity properties. The linear model in the rule consequent is saturated outside the core set of the antecedent membership functions. This allows the interpretation of the consequents of fuzzy rules as a local linearization of the model restricted to the subset where it is valid. The setting has readability advantages over Takagi-Sugeno frameworks, and it is simpler that other interpolation proposals. Some examples illustrate the approach.
Systems Engineering and Control teaching has a problem in common with other technical studies whe... more Systems Engineering and Control teaching has a problem in common with other technical studies when distance learning is required: laboratory lectures. It is related to the studied concepts in the area and the requirement of using specific software tools (i.e. Matlab) and process. This paper presents a global approach for the remote process simulation and real control using Matlab Web Server (MWS) tool. This work allows the execution of Matlab developed applications from any remote computer having a Web browser. The server obtains configuration parameters from a Web page and runs M-file Matlab programs. Once the simulation or the real process control has finished, MWS returns the output results to the remote computer through a new Web Page.
Revista Iberoamericana De Automatica E Informatica Industrial, 2004
Resumen: La aplicación de las técnicas de agrupamiento borroso para la identificación de modelos ... more Resumen: La aplicación de las técnicas de agrupamiento borroso para la identificación de modelos borrosos se está extendiendo cada vez más. Sin embargo, y dado que su origen es bien distinto a la ingeniería de control, aparecen numerosos problemas en su aplicación en la identificación de modelos locales de sistemas no lineales para control. En este trabajo se revisan las principales técnicas de agrupamiento para la identificación de modelos borrosos, incluyendo propuestas propias que permiten desarrollar modelos que mejoran (respecto a algoritmos previamente existentes) la interpretabilidad y el descubrimiento de estructuras afines locales en los modelos borrosos obtenidos.
Proceedings of the 16th IFAC World Congress, 2005, 2005
Applications of Information Technology in Process Control range from control educational tools to... more Applications of Information Technology in Process Control range from control educational tools to real process control. Advantages are related to an increase in flexibility for engineers (specially interesting for industrial operators training in new techniques), a decrease in maintenance and supervision costs and a best managing and performance of the plant.
A continuación, se presenta una metodología que permite a empresas y organizaciones laborales ana... more A continuación, se presenta una metodología que permite a empresas y organizaciones laborales analizar su situación desde el punto de vista de la diversidad de género y la igualdad de oportunidades. El estudio comienza con un análisis estático, considerando cierto instante de tiempo inicial. Una base de conocimiento definida por expertos, se usa para elaborar un diagnóstico acertado y generar un listado de acciones correctoras, con el objetivo de mejorar las posibles deficiencias encontradas. A continuación, basándose en predicciones hechas por expertos, se realiza un análisis dinámico, que considera la evolución natural de la organización a lo largo del tiempo y de las personas que la integran, a partir de los resultados iniciales del análisis estático. El modelo se corrige con cada nueva medición, a partir de las predicciones en instantes previos, evaluando la tendencia de la diversidad y cómo evoluciona.
En este trabajo de investigación se presenta un estudio de las técnicas de reconocimiento de patr... more En este trabajo de investigación se presenta un estudio de las técnicas de reconocimiento de patrones en conjuntos de objetos multidimensionales (i.e., de múltiples dimensiones, atributos o cualidades) y, en concreto, de las técnicas que se usan para agrupar objetos definidos por datos cuantitativos (valores numéricos) y datos cualitativos (valores nominales). Para ello, tras una definición de los conceptos a tratar, se comienza con una introducción al campo donde estas técnicas son más usadas, que es el del llamado descubrimiento de información en bases de datos o Knowledge Discovery in Databases (KDD), uno de cuyos procesos principales es la extracción de información y relaciones de similitud entre los datos, búsqueda de patrones o agrupamiento de datos aparentemente inconexos, técnicas que reciben el nombre común de minería de datos o Data Mining.
El presente artículo recoge los primeros resultados en el diseño de agentes supervisores que coop... more El presente artículo recoge los primeros resultados en el diseño de agentes supervisores que cooperan en el control de robots móviles, mediante la partición del espacio de actuación en áreas de influencia distintas para cada agente, incorporando transiciones de tipo borroso en las zonas en que el robot móvil sigue una trayectoria prefijada pasando de un área de influencia a otra.
IEEE Transactions on Control Systems Technology, 2020
This paper is focused on closed-loop control of postprandial glucose levels of patients with type... more This paper is focused on closed-loop control of postprandial glucose levels of patients with type 1 diabetes mellitus after unannounced meals, still a major challenge towards a fully autonomous artificial pancreas. The main limitations are the delays introduced by the subcutaneous insulin pharmacokinetics and the glucose sensor, which typically lead to insulin over-delivery. Current solutions reported in the literature typically resort to meal announcement, which requires the patient intervention. In this paper, a disturbance observer is used to estimate the effect of unannounced meals and the insulin pharmacokinetics is taken into account by means of a feedforward compensator. The proposed strategy is validated in silico with the UVa/Padova metabolic simulator. It is demonstrated how the disturbance observer successfully estimates and counteracts not only the effect of meals but also sudden drops in the glucose levels that may lead to hypoglycemia. For unannounced meals, results show a median time-in-range of 80% in a 30-day scenario with high carbohydrate content and large intra-subject variability. Optionally, users may decide to announce meals. In this case, considering severe bolus mismatch due to carbohydrate counting errors, the median time-in-range is increased up to 88%. In every case, hypoglycemia is avoided.
A valuable option in complex systems modelling is the use of fuzzy models, but fuzzy modelling sh... more A valuable option in complex systems modelling is the use of fuzzy models, but fuzzy modelling should have interpretability of the obtained models as a fundamental goal. Additionally, some considerations must be taken into account when subsequent use of this models is local model control, provided that it might influence the criteria used in identification for prediction. In this Thesis, after elucidating some unclear concepts found in literature regarding local modelling criteria, desirable characteristics of fuzzy modelling and identification techniques for control purposes are proposed. Behaviuor of objective functions of local-model-control-oriented fuzzy clustering algorithms is studied and a new index is presented so that it incorporates some desirable characteristics regarding convexity and smoothness of the final identified clusters, with advantages regarding other methodologies such as Gustaffson-Kessel. Subsequently, the definition of a family of clustering algorithms for previously defined objective function minimization is done. They lead to a better identification of local models approximating the linearized plant model on their validity zones and with some additional desirable characteristics regarding membership function interpretability (convexity and smoothness). The algorithm simultaneously provided local linear models and input clustering, being specially suitable for Takagi-Sugeno fuzzy models identification and local linear models decomposition of nonlinear systems for control. ix x
A Fick's model that includes a Takagi-Sugeno fuzzy model to estimate the effective diffusivity wa... more A Fick's model that includes a Takagi-Sugeno fuzzy model to estimate the effective diffusivity was analyzed. The modelling of drying kinetics on mango trough this diffusional-fuzzy model was compared with the theoretical Fick's model and the empirical Peleg and Weibull models. The identification and validation was performed from experimental drying curves of ripe mango slices (Mangifera indica L. cv. Tommy Atkins) at constant air velocity (4 m/s) and different drying temperatures (40, 50, 60 and 70 ºC). The fuzzy sets for the antecedent of Takagi-Sugeno system were identified by the Gustafson-Kessel clustering algorithm and approximated by membership functions of piecewise exponential form. On identification and validation, the diffusional-fuzzy model showed best results than the Fick's model, whereas it showed little difference with the Weibull and Peleg models. The diffusional-fuzzy model keeps the interpretability of Fick's model, improves the process simulation and avoids phenomenon and property considerations which require additional experimental and modelling work.
This paper presents an alternative inference-defuzzification algorithm for Takagi-Sugeno fuzzy sy... more This paper presents an alternative inference-defuzzification algorithm for Takagi-Sugeno fuzzy systems that preserves local-model interpretation and convexity properties. The linear model in the rule consequent is saturated outside the core set of the antecedent membership functions. This allows the interpretation of the consequents of fuzzy rules as a local linearization of the model restricted to the subset where it is valid. The setting has readability advantages over Takagi-Sugeno frameworks, and it is simpler that other interpolation proposals. Some examples illustrate the approach.
Systems Engineering and Control teaching has a problem in common with other technical studies whe... more Systems Engineering and Control teaching has a problem in common with other technical studies when distance learning is required: laboratory lectures. It is related to the studied concepts in the area and the requirement of using specific software tools (i.e. Matlab) and process. This paper presents a global approach for the remote process simulation and real control using Matlab Web Server (MWS) tool. This work allows the execution of Matlab developed applications from any remote computer having a Web browser. The server obtains configuration parameters from a Web page and runs M-file Matlab programs. Once the simulation or the real process control has finished, MWS returns the output results to the remote computer through a new Web Page.
Revista Iberoamericana De Automatica E Informatica Industrial, 2004
Resumen: La aplicación de las técnicas de agrupamiento borroso para la identificación de modelos ... more Resumen: La aplicación de las técnicas de agrupamiento borroso para la identificación de modelos borrosos se está extendiendo cada vez más. Sin embargo, y dado que su origen es bien distinto a la ingeniería de control, aparecen numerosos problemas en su aplicación en la identificación de modelos locales de sistemas no lineales para control. En este trabajo se revisan las principales técnicas de agrupamiento para la identificación de modelos borrosos, incluyendo propuestas propias que permiten desarrollar modelos que mejoran (respecto a algoritmos previamente existentes) la interpretabilidad y el descubrimiento de estructuras afines locales en los modelos borrosos obtenidos.
Proceedings of the 16th IFAC World Congress, 2005, 2005
Applications of Information Technology in Process Control range from control educational tools to... more Applications of Information Technology in Process Control range from control educational tools to real process control. Advantages are related to an increase in flexibility for engineers (specially interesting for industrial operators training in new techniques), a decrease in maintenance and supervision costs and a best managing and performance of the plant.
A continuación, se presenta una metodología que permite a empresas y organizaciones laborales ana... more A continuación, se presenta una metodología que permite a empresas y organizaciones laborales analizar su situación desde el punto de vista de la diversidad de género y la igualdad de oportunidades. El estudio comienza con un análisis estático, considerando cierto instante de tiempo inicial. Una base de conocimiento definida por expertos, se usa para elaborar un diagnóstico acertado y generar un listado de acciones correctoras, con el objetivo de mejorar las posibles deficiencias encontradas. A continuación, basándose en predicciones hechas por expertos, se realiza un análisis dinámico, que considera la evolución natural de la organización a lo largo del tiempo y de las personas que la integran, a partir de los resultados iniciales del análisis estático. El modelo se corrige con cada nueva medición, a partir de las predicciones en instantes previos, evaluando la tendencia de la diversidad y cómo evoluciona.
En este trabajo de investigación se presenta un estudio de las técnicas de reconocimiento de patr... more En este trabajo de investigación se presenta un estudio de las técnicas de reconocimiento de patrones en conjuntos de objetos multidimensionales (i.e., de múltiples dimensiones, atributos o cualidades) y, en concreto, de las técnicas que se usan para agrupar objetos definidos por datos cuantitativos (valores numéricos) y datos cualitativos (valores nominales). Para ello, tras una definición de los conceptos a tratar, se comienza con una introducción al campo donde estas técnicas son más usadas, que es el del llamado descubrimiento de información en bases de datos o Knowledge Discovery in Databases (KDD), uno de cuyos procesos principales es la extracción de información y relaciones de similitud entre los datos, búsqueda de patrones o agrupamiento de datos aparentemente inconexos, técnicas que reciben el nombre común de minería de datos o Data Mining.
El presente artículo recoge los primeros resultados en el diseño de agentes supervisores que coop... more El presente artículo recoge los primeros resultados en el diseño de agentes supervisores que cooperan en el control de robots móviles, mediante la partición del espacio de actuación en áreas de influencia distintas para cada agente, incorporando transiciones de tipo borroso en las zonas en que el robot móvil sigue una trayectoria prefijada pasando de un área de influencia a otra.
Uploads
Papers by Jose Luis Diez