Instructional feedback based continuous evaluation: an analysis from the control theory point of view

The instructional feedback model establishes a parallelism among a feedback control automated system and the relationships between the teacher/instructor and the student/learner. In such a model the teacher/instructor is assumed to be the controller or provider of energy to the system to be controlled (the student’s/learner skills and competences on a specific subject). The instructional feedback is a closed loop model that relies on receiving feedback from the students/learners and to generate different actions to modify its learning performance. In this communication the idea of instructional feedback is reviewed and slightly reformulated highlighting the necessity and importance of another feedback loop that has to be closed on the student/learner side as well as providing the means for this. On the conventional instructional feedback model the feedback is received at the teacher/instructor side, whereas it is, on the author’s opinion, at the student side that has to be closed in order to be effective.Postprint (published version

Human intervention and interface design in automation systems

Human-Machine-Interfaces are with no doubt one of the constitutive parts of an automation system. However, it is not till recently that they have received appropriate attention. It is because of a major concern about aspects related to maintenance, safety, achieve operator awareness, etc has been gained. Even there are in the market software solutions that allow for the design of efficient and complex interaction systems, it is not widespread the use of a rational design of the overall interface system, especially for large scale systems where the monitoring and supervision systems may include hundreds of interfacing screens. It is on this respect hat this communication provides an example of such development also by showing how to include the automation level operational modes into the interfacing system. Another important aspect is how the human operator can enter the control loop in different ways, and such interaction needs to be considered as an integral part of the automation procedure as well as the communication of the automation device.In this paper the application of design and operational modes guidelines in automation are presented inside an educational flexible manufacturing system case study.Postprint (published version

Nash Solution as a Multi-Criteria Decision Making Technique for Control Problems

[Abstract] A control system problem can be viewed as a multiobjective problem due to the fact that there are many requirements to be satisfied. Nowadays, multi-objective optimization deals with this kind of problem by implementing optimization techniques, capable of searching for the Pareto set approximation, hereafter the designer needs to select the best solution that provides a good trade-off among the competitve objectives from the Pareto front approximation. Therefore, in this communication we address the problem of selecting the best trade-off between the conflictive objectives, this stage is called the Multi-Criteria Decision Making (MCDM). In this paper we propose to use the Nash solution as a tuning technique to select the design alternative to implement on the control system. This selection is compared with others Proportional-Integral (PI) tuning rules on the literature.This work has received financial support from the Spanish Ministry of Economy and Competitiveness program under grant DPI2013-47825-C3-1-R. The financial support from the University of Costa Rica, under the grants 322-B4-218 and 731-B4-213, is greatly appreciatedUniversidad de Costa Rica; 322-B4-218Universidad de Costa Rica; 731-B4-213https://doi.org/10.17979/spudc.978849749808

Robust 2-DoF PID control for Congestion control of TCP/IP Networks

This paper presents how Robust PID control can improve the performance of congesion control on TCP/IP networks. The proposed approach is compared with other control methods, such as PI control or RED/AQM, showing the advantages of the proposed technique

A Recurrent Neural Network for Wastewater Treatment Plant Effuents' Prediction

[Abstract] Wastewater Treatment Plants (WWTP) are industries devoted to process water coming from cities' sewer systems and to reduce their contamination. High-pollutant products are generated in the pollutant reduction processes. For this reason, certain limits are established and violations of them are translated into high economic punishments and environmental problems. In this paper data driven methods are performed to monitor the WWTP behaviour. The aim is to predict its effluent concentrations in order to reduce possible violations and their derived costs. To do so, an alarm generation system based on the application of Artificial Neural Networks (ANNs) is proposed. The proposed system shows a good prediction accuracy (errors around 5%) and a reduced miss-detection probability (30%).[Resumen] Las Plantas de tratamiento de aguas residuales (PTAR) son industrias dedicadas a procesar el agua que proviene de los sistemas de alcantarillado de las ciudades y reducir su contaminación. Los productos de alta contaminación se generan en los procesos de reducción de contaminantes. Por esta razón, se establecen ciertos límites y sus violaciones se traducen en castigos económicos elevados y problemas ambientales. En este documento, se realizan métodos controlados por datos para monitorizar el comportamiento de la EDAR. El objetivo es predecir sus concentraciones de efluentes para reducir las posibles violaciones y sus costos derivados. Para ello, se propone un sistema de generación de alarmas basado en la aplicación de Redes Neuronales Artificiales (ANN). El sistema propuesto muestra una buena precisión de predicción (errores en torno al 5%) y una probabilidad de detección errónea reducida (30%).Ministerio de Economía y Empresa; DPI2016-77271-

Análisis cuantitativo de estilos de aprendizaje y satisfacción en contextos de aprendizaje basado en proyectos de accesibilidad

Este trabajo se centra en el análisis cuantitativo mediante técnicas estadísticas de clasificación al problema del estudio de los estilos de aprendizaje (superficial, profundo) y la satisfacción de los estudiantes en el marco de asignaturas universitarias centradas en el aprendizaje de la accesibilidad y gestión de proyectos académicos. Los principales resultados hacen hincapié en la predominancia del estilo profundo respecto al superficial y en la significancia estadística entre estilos de aprendizaje y satisfacción.Postprint (published version

Human Intervention and Interface Design in Automation Systems

Human-Machine-Interfaces are with no doubt one of the constitutive parts of an automation system. However, it is not till recently that they have received appropriate attention. It is because of a major concern about aspects related to maintenance, safety, achieve operator awareness, etc has been gained. Even there are in the market software solutions that allow for the design of efficient and complex interaction systems, it is not widespread the use of a rational design of the overall interface system, especially for large scale systems where the monitoring and supervision systems may include hundreds of interfacing screens. It is on this respect hat this communication provides an example of such development also by showing how to include the automation level operational modes into the interfacing system. Another important aspect is how the human operator can enter the control loop in different ways, and such interaction needs to be considered as an integral part of the automation procedure as well as the communication of the automation device.In this paper the application of design and operational modes guidelines in automation are presented inside an educational flexible manufacturing system case study

Effects of Vine Water Status on Yield Components, Vegetative Response and Must and Wine Composition

Despite Vitis vinifera L. is a drought-tolerant species—rainfed traditionally grown in a very diversity of climates—irrigation has more and more become a usual practice aimed to obtain regular yields along seasons and to control must composition. Results on vineyard irrigation are dependent on the timing, length and intensity of the water deficit. From budbreak to flowering, shoot growth is very sensitive to water stress, while reproductive growth is almost unaffected. Severe water deficit during fruit set can reduce yield by affecting ovary cell multiplication and expansion. During maturation water stress induces yield reduction by limiting berry growth; along this phase must composition is also affected. There is a positive, linear relationship between must sugar content and available water; however, no relationship has been found to either total acidity or pH. Biosynthesis of anthocyanins and fruity aromas is enhanced by water deficit. Usually, wines from moderate irrigation treatments scored the highest. There is a general agreement that severe, long water deficits diminish must quality, leaf area, fertility and yield, and it has a negative carryover effect on the next seasons by limiting wood reserves to be used the following seasons

Digital Control of a Waste Water Treatment Plant

The Activated Sludge Process (ASP) is arguably the most popular bioprocess utilized in the treatment of polluted water. The ASP is described by means of a nonlinear model and results on a Two-Input Two-Output multivariable system. In this paper a discrete time digital control is proposed where the design of a decentralized controller is faced. Local controllers are given the form of a Two-Degree-of-Freedom PI controller tuned using the data-driven Virtual-Reference Feedback tuning approach

Feed-forward control for a drinking water treatment plant chlorination process

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Chlorination in drinking water treatment plants (DWTP) is the final process applied to water before it is sent to storage tanks in the supply network for subsequent human consumption. An excessive dosage of chlorine or, conversely, too small a dosage, may breach existing legal regulations on mandatory limits. In DWTP where there is no significant variability in the quality of the water to be treated, a type of control that is proportional to the flow rate in the effluent can have fully satisfactory results. Therefore, Proportional-Integral (PI) control is a rather frequently used solution. However, when there are inherently long delays in the process, variability in the quality of the water to be treated and considerable variations alternative type is needed. This article presents the strategy and results of a control method that proposes a Fuzzy based feed-forward system to complement an existing PI control. The control system results are shown as applied to the DWTP of Barcelona city, producing satisfactory experimental results.Postprint (author's final draft