- Prof. C. Verde joined the National Autonomous University from Mexico in 1984 and received the 2005 Sor Juana Ines de... moreProf. C. Verde joined the National Autonomous University from Mexico in 1984 and received the 2005 Sor Juana Ines de la Cruz Prize for outstanding women. She is author and coauthor of over 150 papers published in conferences and journals. Her main topic of research is robust fault detection of industrial processes.edit
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This paper presents a new approach to synchronize spatio-temporal systems including parametric identification as goal. The paper concentrates on generalized synchronization with a so-called Master-Slave (unidirectional) topology. The... more
This paper presents a new approach to synchronize spatio-temporal systems including parametric identification as goal. The paper concentrates on generalized synchronization with a so-called Master-Slave (unidirectional) topology. The approach deals with the construction of a nonlinear observer to estimate the parameters of a Master system, such that the estimates can be used on-line by a Slave system to synchronize with the Master. Both, the Master and the Slave system, are approximated by the Finite Difference Method.
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In this paper an observer-based fault diagnosis system is proposed for a Maximum Power Point Tracker (MPPT) BOOST converter in photovoltaic (PV) systems. Open- and Short-circuit switch faults can be diagnosed by the Fault Detection and... more
In this paper an observer-based fault diagnosis system is proposed for a Maximum Power Point Tracker (MPPT) BOOST converter in photovoltaic (PV) systems. Open- and Short-circuit switch faults can be diagnosed by the Fault Detection and Isolation (FDI) algorithm suggested in this study. A decoupled subsystem from the load and PV currents is obtained for residual generation, which is guaranteed at the price of 2 measurements, namely, PV current and load voltage. Hence, the FDI system is insensitive to load changes and sudden irradiance drops. According to observability properties of this subsystem, the fault detection time can be assigned arbitrarily. In addition, operation of the FDI system in open- and closed-loop has been evaluated through a prototype of 350 W. Only the most common measurements employed into the Maximum Power Point searching techniques are required in the proposed FDI system. Finally, as an important result, the proposed FDI system can be applied over the most common PV applications due to the residual generation system is decoupled from load conditions.
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Abstract This paper deals with the problem of detection and identification of sequential leaks which are non-strong isolable. To solve the problem in the framework of model-based procedures, a nonlinear input-output model with five state... more
Abstract This paper deals with the problem of detection and identification of sequential leaks which are non-strong isolable. To solve the problem in the framework of model-based procedures, a nonlinear input-output model with five state is proposed which is equivalent to the fluid model with multiple faults in steady-state. This input-output model has the property to retain the data of the past leaks allowing only the identification on-line of the new event during a time window for any arbitrary number of leaks. Specifically, two sets of parameters characterize each event in the model: one set associated with the past events in the equivalent leak's model and the second one which contains the latest event parameters. Thus, an iterative Fault Detection and Isolation scheme is suggested which identifies each time a new leak is present its outflow an position, together with the equivalent model by using adaptive Extended Kalman Filters. The simulation for a sequential set of three leaks shows successful results.
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Hoy en dia, la obesidad es el quinto factor de riesgo de mortalidad a nivel mundial; afecta a un 29% de la poblacion mundial. Poco a poco, a la sociedad se comienza a interesar cada vez mas por la salud del cuerpo y la estetica. Por esta... more
Hoy en dia, la obesidad es el quinto factor de riesgo de mortalidad a nivel mundial; afecta a un 29% de la poblacion mundial. Poco a poco, a la sociedad se comienza a interesar cada vez mas por la salud del cuerpo y la estetica. Por esta razon, la sociedad invierte con mayor frecuencia en los tratamientos de nutricion elaborados por especialistas del sector. De hecho, el sector medico-estetico posee una tasa de crecimiento anual del 15%. Actualmente, la manera de cuantificar la eficacia del tratamiento nutricional de una persona es a traves de un seguimiento dimensional con fotografias o mediante una cinta metrica. Por esta razon, se origina la problematica de encontrar un metodo de seguimiento de tratamientos medico-esteticos preciso y sencillo de utilizar. Debido al avance de las tecnologias, este proyecto tiene como mision estudio de la posibilidad de encontrar un metodo de diagnostico que sea capaz de cuantificar los resultados de los tratamientos de manera precisa, sencilla y revolucionaria. Para ello, se podrian elaborar modelos tridimensionales de los pacientes mediante escaneres 3D. De esta manera, una vez efectuado el modelo del individuo, analizar tanto cualitativamente como cuantitativamente como de efectivo esta siendo este tratamiento. De esta manera, aportar a los especialistas de una herramienta intuitiva y precisa de diagnostico. En este trabajo, se han utilizado dos escaneres tridimensionales distintos: la camara de 3D Sense y la camara de Kinect. Se han efectuado pruebas experimentales con ambos escaneres. Con la finalidad de que el proceso de construccion de modelos 3D fuera mas rapido y repetitivo, se ha utilizado una plataforma giratoria durante el proceso de escaneado. La plataforma ha facilitado, sin duda, la toma de imagenes. Con el uso de la plataforma, el proceso de escaneado era mas comodo para el usuario. Durante la fase de experimentacion, se ha llegado a la conclusion de que la camara de Kinect toma mejor las imagenes. Se producen menos modelos con problemas como huecos y bordes partidos. Sin embargo, no se ha llegado a efectuar una toma de imagenes de un modelo de una persona completo en un solo escaneado. Este problema viene de que el sistema de barrido es de tipo camara, es decir, viene limitado a un ancho de escena especifico, delimitado por el tamano de la ventana de barrido, que puede ser de un maximo de 60o tanto en angulo horizontal como en vertical. Posteriormente, se ha elaborado un estudio de los softwares de tratamiento de imagenes tridimensionales con el fin de encontrar una plataforma que permita rebanar al objeto por donde se desee. De esta manera, se ha elaborado un analisis dimensional del individuo. Para ello, se han probado distintos softwares. Los softwares utilizados que han producido resultados prometedores han sido DesignSpark y Meshmixer. Con primero de ellos, se han efectuado cortes por planos paralelos y entonces, se han medido tanto las dimensiones en la direccion X como en la direccion Y, como el perimetro del objeto. Analogamente, con Meshmixer se ha utilizado una herramienta propia del programa con el fin de dividir el objeto por planos perpendiculares al eje Z y se han medido las dimensiones en los ejes X e Y, como en el DesignSpark. Meshmixer, es un programa mas intuitivo con el que trabajar, pero no permite medir perimetros. Finalmente, se han analizado las variables que han influido durante el proceso de escaneado. Entre ellas se encuentra la iluminacion, el modelo debe situarse en un entorno iluminado. El fondo de la sala debe ser liso y claro para evitar la posibilidad de que interfiera en la toma de datos y se produzca un efecto de borde partido. El tiempo de escaneado debe ser en torno a los tres minutos, dando dos vueltas a la plataforma para captar mas informacion a una velocidad parcialmente moderada. Por ultimo, la plataforma debe situarse entre 90 centimetros y 1 metro de la torre en la que se encuentra el escaner. En conclusion, ha sido una gran satisfaccion aunar en este proyecto los campos de la medicina y de la ingenieria. En un futuro, se podria continuar en esta linea de investigacion llegando a obtener un modelo completo del individuo, agilizar y conciliar el proceso de escaneado y automatizar el analisis de dimensional para llegar a una un producto final que reuniera todas las caracteristicas que desea este proyecto.
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This paper presents a new approach to synchronize spatio-temporal systems including parametric identification as goal. The paper concentrates on generalized synchronization with a so-called Master-Slave (unidirectional) topology. The... more
This paper presents a new approach to synchronize spatio-temporal systems including parametric identification as goal. The paper concentrates on generalized synchronization with a so-called Master-Slave (unidirectional) topology. The approach deals with the construction of a nonlinear observer to estimate the parameters of a Master system, such that the estimates can be used on-line by a Slave system to synchronize with the Master. Both, the Master and the Slave system, are approximated by the Finite Difference Method.
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Research Interests: Estimator and Excitation
This work presents an active fault-tolerant control (FTC) scheme by damping injection for a wave energy converter (WEC). The case study is an Archimedes wave swing-based WEC, where two braking subsystems for the floater play a critical... more
This work presents an active fault-tolerant control (FTC) scheme by damping injection for a wave energy converter (WEC). The case study is an Archimedes wave swing-based WEC, where two braking subsystems for the floater play a critical role in protecting the physical structure from extreme sea conditions. In order to obtain fault-tolerant behavior in the presence of faults in the brakes, the deviation of the damping force is compensated through the force produced by the linear generator, which is controlled to maximize the energy conversion in nominal conditions. For this purpose, the force deviation is estimated from a fault detection and isolation (FDI) module by using an Utkin-based unknown input observer, which is then used for the compensation that completes the FTC. The proposed system is tested by numerical simulation under different scenarios, including faults in the damping system and others. The results demonstrate the capabilities and limitations of the proposal, which achieves the established objective. The performances of the nominal control and the proposed FTC are compared.
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Leakages in Water Distribution Networks cause significant economical losses as well as environmental damage. Therefore, this paper proposes a novel leak location approach. The proposed method consists in using a modified differential... more
Leakages in Water Distribution Networks cause significant economical losses as well as environmental damage. Therefore, this paper proposes a novel leak location approach. The proposed method consists in using a modified differential evolution (DE) algorithm to solve the leak location task as an inverse problem based on the network’s hydraulic model. The modified DE algorithm considers the topological characteristics of the network. Temporal reasoning of the results is integrated with the proposal to improve the leak location performance. The strategy was tested under different uncertainty conditions with the model of the Modena water distribution network showing a performance ranging from 94 to 98% leak location accuracy with reduced zone sizes compared to previous approaches based on data-driven classification tools.
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A novel approach for the continuous detection of leaks in water distribution networks (WDNs) assuming uncertain demand patterns is presented. The proposal is based on a demand pattern construction with repetitive multiple statistic models... more
A novel approach for the continuous detection of leaks in water distribution networks (WDNs) assuming uncertain demand patterns is presented. The proposal is based on a demand pattern construction with repetitive multiple statistic models which allow detection through residual generation for each corresponding model. The key of the method is the time division of the pattern such that the demand satisfies the stationarity condition during each time interval. Thus, the sequential set of demand models allows the use of traditional multivariate statistical tool such as principal component analysis (PCA) for the monitoring of each interval in a sequential manner. Simulations with an academic network are used to test the performance of the proposal, and the results show a lower false alarm rate than the standard PCA.
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This article presents a method to estimate frequency distributions of the parameters associated with the presence of two leaks in a main water pipeline: the locations and the emitter coefficients. Since the method is offline, it can be... more
This article presents a method to estimate frequency distributions of the parameters associated with the presence of two leaks in a main water pipeline: the locations and the emitter coefficients. Since the method is offline, it can be used to locate simultaneous or sequential leaks; the only requirement is that both leaks must be present when the data for diagnosis are acquired. The method requires as input information pressure and flow rate data to be measured at the pipeline boundaries. In a first stage, hydraulic quasi-steady state relations are computed by using the input information. These relations are used to calculate hydraulic and spatial constraints. In a second stage, Monte Carlo simulations are used together with the previously defined restrictions to obtain frequency distributions of the parameters associated with both leaks. To test the feasibility and potentiality of the method, it was implemented and tested in MATLAB with synthetic data.
Research Interests: Computer Science, Monte Carlo Simulation, Monte Carlo, Water Distribution Systems, Matlab, and 8 moreMonte Carlo Simulations, Water Distribution Networks, Pipelines, Leak detection, Data Leakage Detection, Monte Carlo Method, Montecarlo Simulation, and Leakage management in urban water networksks in developing countries
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Research Interests: Information Theory, System Identification, Structural Dynamics, Independent Component Analysis, Blind Source Separation, and 12 moreFinite Element, Model Updating, Anomaly Detection, Wavelets, Computational Efficiency, Wave propagation, Approximate Entropy, Output Only Modal Analysis in Shm, Aluminum Alloy, Machine Health Monitoring, Modal Strain Energy, and Objective function
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This paper introduces a novel technique to reconstruct unmeasured outflow rates in pipelines with two branches, where only input-output flow rate and pressure information is available, by using High-Order Sliding Mode Observers and by... more
This paper introduces a novel technique to reconstruct unmeasured outflow rates in pipelines with two branches, where only input-output flow rate and pressure information is available, by using High-Order Sliding Mode Observers and by exploiting the stable nature of the physical operation point. The performance of the technique is tested through simulation and by using experimental data from a pilot pipeline. A comparison with a First-Order Sliding Mode Observer in a cascade scheme is also performed. The proposed approach is particularly useful for estimating unknown signals in stable systems, which possess the Strictly Linked Upper and Lower Hessenberg structure.
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In this paper, it is proposed to estimate the robustness of a closed loop system by a error model which is obtained calculating the difference between the transfer matrix of the closed loop system with nominal and uncertain plant. For the... more
In this paper, it is proposed to estimate the robustness of a closed loop system by a error model which is obtained calculating the difference between the transfer matrix of the closed loop system with nominal and uncertain plant. For the estimation it is assumed an approximated model of the uncertainty in frequency domain. An advantage of this error model is its generality since it allows to consider additive, multiplicative or feedback uncertainty Δ. Additionally, here it is introduced a procedure based on this estimation to select the signals spectrum which must be weighted in the objective function used to synthesize linear controller. This procedure simplifies the task to weight signals in the frequency domain cost to be minimized, which could become a difficult job, specially for MIMO systems. Specifically, considering the standard H∞ optimal control problem, the approach is validated with two design problems.
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This paper describes a diagnosis scheme based on a distributed adaptive observer identifying a shunt fault of a long transmission line. A conductance deterioration in a specific point is assumed. Considering that the hyperbolic partial... more
This paper describes a diagnosis scheme based on a distributed adaptive observer identifying a shunt fault of a long transmission line. A conductance deterioration in a specific point is assumed. Considering that the hyperbolic partial differential equations govern the electric transmission line, fault location and estimation are obtained by means of an adaptive distributed observer with only available measurements at the boundary. The key ingredient in the approach is the separation of the fault magnitude in the model from its position into two consecutive tasks. This is achieved by means of an adequately selected canonical transformation of original variables and an adaptive observer design for the transformed system. The effectiveness of the approach is illustrated by a numerical simulation in a long electrical transmission line of 300km.
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This article presents an approach based on a state observer to calibrate the Hazen-Williams (HW) equation, which is widely used to model the head loss in a pipeline. To perform the calibration process, the approach requires a record over... more
This article presents an approach based on a state observer to calibrate the Hazen-Williams (HW) equation, which is widely used to model the head loss in a pipeline. To perform the calibration process, the approach requires a record over time of the flow rate, which can be taken in any coordinate along the pipeline, and a record of the pressure taken at the inlet. Specifically, the proposed approach allows estimating both the roughness coefficient involved in the HW equation and the hydraulic head at the pipeline outlet. The closure of this contribution presents some results involving data that were collected during experiments in a physical model. Such results show the feasibility of implementing the proposed approach.
Research Interests: Control Systems Engineering, Mathematics, Computer Science, Water Distribution Systems, Control Systems, and 15 moreState Estimation, Calibration, Model Calibration, Offshore Pipelines, Water Distribution Network Design and Calibration, Friction Correction Factor, Water Distribution Networks, Pipelines, Extended State Observer, Water Pipelines, Nonlinear State Estimation, Submarine Pipelines, Water Distribution Network, Fourier Series, and Friction Factor
In this work, an adaptive observer is designed to detect a uniform electric long transmission line failure by considering a distributed parameter’s model where both voltage and current at the line ends are measurable. In particular,... more
In this work, an adaptive observer is designed to detect a uniform electric long transmission line failure by considering a distributed parameter’s model where both voltage and current at the line ends are measurable. In particular, deterioration of the resistance R and conductivity G per-unit length are considered the parameters with abnormal conditions. To avoid numerical problems during the design and to generalize the results, the distributed system and the excitation are transformed into a dimensionless model before the estimation problem formulation. Based on this model, a distributed observer with boundary injections is designed. Thus, this observer’s output errors can be used as a residual generator for the detection of the resistance and conductivity deterioration. An adaptive observer is constructed by combining the distributed observer and a set of updating rules to identify the parameter deviations. A long transmission line is adopted as a case study to show the feasibility of the proposition for transmission line monitoring with two different generator signals in simulations.
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We present a simple and highly accurate computa-tional method for operon prediction, based on intergenic distances and functional relation-ships between the protein products of contiguous genes, as defined by STRING database
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A multi-objective approach for sensor placement in water distribution networks (WDNs) is presented in this paper. The performance of leakage detection and localization methods highly depends on the amount, type and placement of the... more
A multi-objective approach for sensor placement in water distribution networks (WDNs) is presented in this paper. The performance of leakage detection and localization methods highly depends on the amount, type and placement of the sensors installed in the network. Sensor placement is a challenging task considering the demand uncertainties, measurement noise, and varying leakage size. While some sensor placement methods have been designed to maximize leakage detection, others have been developed for leakage localization. In practice, both tasks are relevant. Thus, the goal of obtaining a sensor configuration that establishes a compromise between leak detection and localization errors is considered here. The sensor placement task is then formulated as a multi-objective optimization problem. A real-life and large-scale network that represents a version of the distribution system of the Modena city is used as a case study with synthetically generated data. The feasibility of the proposal is demonstrated for scenarios with demand uncertainty, measurements noise and varying leakage size.
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Abstract This article presents a procedure, which is formulated in three stages, to simplify the problem of localizing a single leak in a pipeline with multiple branches. The first two stages involve the fulfillment of generic conditions... more
Abstract This article presents a procedure, which is formulated in three stages, to simplify the problem of localizing a single leak in a pipeline with multiple branches. The first two stages involve the fulfillment of generic conditions deduced from head loss and flow rate balances for detecting and locating the specific section where the leak is present. The fulfillment of these conditions allows finding the analytical expression for the leak localization, which is the goal of the third stage. The key point of the procedure is the search for the section where the leak is found, which is based on a search for similarity between two types of models that depend, respectively, on measured and estimated hydraulic variables. To support the generality of the analytical expression for the leak localization, it is used to derive previously reported particular expressions for localizing leaks in single-branch pipes. The simplicity of the procedure is demonstrated by numerical simulations. Its performance under real conditions is demonstrated with field data of a 60-km long LPG pipeline in which the correct section with abnormal events is determined, despite uncertain data.
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A novel leak location approach for large-scale water distribution networks (WDNs) is discussed in this paper. The location task is formulated as a classification problem, and it is simplified by applying a clustering strategy. Data from... more
A novel leak location approach for large-scale water distribution networks (WDNs) is discussed in this paper. The location task is formulated as a classification problem, and it is simplified by applying a clustering strategy. Data from each class are formed by measurements associated with leakages that occur within a specific zone of the WDN. A zone is defined as a set of nodes that share similar topological properties. Therefore, clustering is performed for network partitioning. Sensors are then placed within the network for maximizing leak detection coverage, and data of each class are generated by using the EPANET hydraulic simulator. The robustness of the proposal is demonstrated for different kinds of uncertainties and measurements’ noise. A real-life network is used as case study with synthetically generated field data. The proposal achieves an improved performance for the different scenarios in comparison with the node location approach.
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This paper presents a model for describing the flow of a mixture of water and glycerol in pressurized horizontal pipelines. The model is constituted by mass and momentum conservation equations together with experimental formulas for... more
This paper presents a model for describing the flow of a mixture of water and glycerol in pressurized horizontal pipelines. The model is constituted by mass and momentum conservation equations together with experimental formulas for computing both the density and dynamic viscosity of the mixture. The model was programmed in MATLAB to be numerically solved, as well as to simulate flow with different fractions of water and glycerol in leaking pipelines, which could allow to conceive algorithms for diagnosing leaks during the transport of flows with high viscosity. To show the agreement between the model prediction and the actual flow behavior of the mixture, the numerical model solution, for certain boundary conditions, is compared with some data acquired during an experimental test in a laboratory pipeline.
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This work deals with the hydraulic gradient estimation in real-time of a transport pipeline computational model by considering a slightly compressible fluid and slightly deformable conduit walls. Since the hydraulic gradient (J(Q)) caused... more
This work deals with the hydraulic gradient estimation in real-time of a transport pipeline computational model by considering a slightly compressible fluid and slightly deformable conduit walls. Since the hydraulic gradient (J(Q)) caused by the friction phenomenon in a pipeline plays an important role in the system's behavior, and this function is affected by fluid properties' deviations, environmental disturbances and conduit deteriorations, it is proposed that the on-line estimation of J(Q) could be part of a monitoring system. The proposition can be applied to obtain computational models of a line with a junction and assumes only measurements of pressure and flow rate at the ends of the conduit and the junction outflow. The generic form of the gradient function J(Q) is a second-order polynomial with coefficients that involve indirectly pipe roughness, the transversal area of the conduit, fluid viscosity and elements connected to the line. The extended Kalman filter (EKF)...