SFC++: A tool for developing distributed real time control

WESIC'98, Girona, Spain June 10, 11 and 12, 1998This paper describes a visual tool for developing real time software for the control of distributed manufacturing systems. The aim of this project, currently in progress, is to get a visual programming environment which integrates both the advantages of object oriented modelling for the design and simulation of systems and the power of modern distributed control systems (i.e. computers with real time operating systems interconnected by means of industrial real time networks). To bridge the gap between the object oriented system model and the implementation level, at which we have multiple parallel tasks running over a network, Sequential Function Charts are used as a standard formalism (IEC, 1988; UTE, 1992) for the description of system dynamics and control software programmin

Preliminary design study of a fuzzy tracking controller applied to a crane type manipulator

[Abstract] The main purpose of a control system is usually to force the output to follow a reference input with zero steady state error while satisfying certain transient requirements such the settling time for rapid following, overshoot and smoothness of the transient response. This paper is concerned with finding a fuzzy rule-based controller achieved by learning from a virtual feedback (PID) controller capable for satisfying rapid following, zero steady state error and overshoot suppression applied to robotized manipulators dedicated to heavy loads or big container handlin

Hybrid FDI on chemical plants

[Abstract] This paper illustrates an alternative implementation to automatic protection and supervision task using the basic principles of model-based fault-detection and isolation associated to the rule-based FDI with subsequent appropriate corrective actions. Hybrid systems may be precisely described by sequential function charts (SFC). Operation supervision of hybrid systems may be carried out simultaneously on the basis of such SFC description. As discrete event and continuous processes operate simultaneously in close cooperation, a strategy to diagnose such hybrid system by means of a structured methodology under SFC description tool on the IEC-848 standard is develope

The linear model of an unknown dynamic process

4th World Congress on Computational Mechanics, 1998, Buenos Aires, Argentina[Abstract] This work describes a novel algorithmic approach to find the linear model of any dynamic process. Dynamic behaviour as a knowledge concept is acquired by means of proposed learning algorithm, being supported by DAM (deterministic associative memory) system. Depending on the particular use of process model, (system simulation, control design, reproduction of dynamic behaviour, parameter identification, plant diagnosis...) information to and from DAM will be stored and retrieved as demanded from a particular application by applying the proposed algorithmic methodolog

Application of simulation to mechanical fault diagnosis by pattern matching with parity equations

[Abstract] The operation of technical processes requires increasingly advanced supervision and fault diagnosis procedures to improve reliability, safety and global efficiency. Simulation associated to signal analysis techniques offers an alternative solution to the field of detection and diagnosis. This paper deals with a basic method in supervision and fault diagnosis of mechanical equipment using simulation procedures to determine both, the ideal dynamic pattern and the faulty dynamic pattern. Then comparison of actual vibration spectrum with both patterns for extract a valid conclusion is the aim of thi

De los reguladores convencionales a los reguladores basados en lógica difusa

[Resumen] En este trabajo se revisan los conceptos de control industrial referido a tareas de control típicamente afrontadas por medio de reguladores PID convencionales y que son susceptibles de ser resueltas mediante reguladores basados en reglas. Se proponen estrategias de compensación correctiva a partir de las acciones básicas de regulación mediante reglas difusas, así como la implementación de reguladores basados en reglas a partir del conocimiento adquirido acerca de los reguladores convencionale

México : un eje central en el desarrollo de las redes hispanas

Esta crónica describe la evolución del Análisis de Redes Sociales (ARS) realizado en México durante los últimos 45 años, con el objetivo de presentar su historia, sus actores principales, y su actividad interna e internacional. Para ello, se relatan los orígenes del análisis estructural mexicano desarrollado por investigadores aislados y su evolución hacia grupos institucionalizados. En segundo lugar presentamos (a) las líneas de investigación más productivas que emplean estrategias de ARS, (b) los equipos de investigación que utilizan activamente esta metodología y (c) los principales eventos académicos celebrados en México dedicados al estudio de las redes sociales. Además repasamos las contribuciones efectuadas por investigadores mexicanos en el evento de referencia en el área (los Sunbelt de la INSNA) del período 2001-2014 y los artículos publicados en la revista Redes: Revista Hispana para el Análisis de Redes Sociales, desde su lanzamiento. Finalmente, proponemos algunas directrices estratégicas para consolidar la institucionalización del ARS en la academia mexicana.This chronicle describes the evolution of Social Network Analysis (SNA) held in Mexico in the past 45 years, with the aim of presenting its history, its major actors and its domestic and international activity. To do this, the origins of the Mexican structural analysis developed by individual researchers and their evolution towards institutionalized groups are reported. Secondly we present (a) the most productive lines of research using SNA strategies, (b) the research teams actively using this methodology, and (c) the major academic events held in Mexico dedicated to the study of social networks . In addition we review the contributions made by Mexican researchers in the landmark event in this area (the Sunbelts) from 2001 to 2014, and the articles published in the journal Redes: Revista Hispana para el Análisis de Redes Sociales, since its launch. Finally, we propose some strategic guidelines to consolidate the institucionalition of SNA in Mexico's academia

New observations of the extended hydrogen exosphere of the extrasolar planet HD209458b

Atomic hydrogen escaping from the planet HD209458b provides the largest observational signature ever detected for an extrasolar planet atmosphere. However, the Space Telescope Imaging Spectrograph (STIS) used in previous observational studies is no longer available, whereas additional observations are still needed to better constrain the mechanisms subtending the evaporation process, and determine the evaporation state of other `hot Jupiters'. Here, we aim to detect the extended hydrogen exosphere of HD209458b with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST) and to find evidence for a hydrogen comet-like tail trailing the planet, which size would depend on the escape rate and the amount of ionizing radiation emitted by the star. These observations also provide a benchmark for other transiting planets, in the frame of a comparative study of the evaporation state of close-in giant planets. Eight HST orbits are used to observe two transits of HD209458b. Transit light curves are obtained by performing photometry of the unresolved stellar Lyman-alpha emission line during both transits. Absorption signatures of exospheric hydrogen during the transit are compared to light curve models predicting a hydrogen tail. Transit depths of (9.6 +/- 7.0)% and (5.3 +/- 10.0)% are measured on the whole Lyman-alpha line in visits 1 and 2, respectively. Averaging data from both visits, we find an absorption depth of (8.0 +/- 5.7)%, in good agreement with previous studies. The extended size of the exosphere confirms that the planet is likely loosing hydrogen to space. Yet, the photometric precision achieved does not allow us to better constrain the hydrogen mass loss rate.Comment: Accepted for publication in Astronomy & Astrophysics. 5 pages, 3 figure

Virtual intelligent sensors on wide plant control applications: an approach

[Abstract] This paper describes a simple and reliable method to acquire information instantaneously on the basis of predictive computations of data acquired with significant time delay. The estimated value of any measured variable is the output of a virtual sensor implemented by means of a virtual engineering programming too