DSpace Repository :: Browsing by Subject "ANALISIS DE FALLAS"

Browsing by Subject "ANALISIS DE FALLAS"

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AI gateway: detección automática de fallas en maquinaria industrial
(2021-02-17) Ivulich, Santiago; Juárez, Diego; Lifschitz, Tobías; Zitelli, Maximiliano
"En el presente informe se documenta el diseño y desarrollo de un equipo electrónico para MAPER TECNOLOGÍA SRL, que permite dar conectividad a sus sensores de vibración industriales de bajo consumo, comunicándose con su servidor en la nube y procesando sus mediciones en busca de anomalías. Estos sensores son utilizados por la empresa para realizar un análisis sobre las vibraciones de equipos rotantes permitiendo anticiparse a posibles fallas en la maquinaria."
Análisis de una falla de una pieza de una empresa automotriz
(2006) Algorta, Ignacio; Galíndez, María del Carmen; Sabaini, Hernán
"El trabajo consiste en el desarrollo de un nuevo método para el análisis de falla de una pieza defectuosa. Al principio se realiza una descripción actual, en la cual se demuestran los altos costos por ineficiencia, la falta de responsabildiades que se traducen en la falta de un método específico y eficiente de resolución de problemas."
Analysis of invariants for efficient bounded verification
(2010-07) Galeotti, Juan Pablo; Rosner, Nicolás; López Pombo, Carlos G.; Frías, Marcelo
"SAT-based bounded veri cation of annotated code consists of translating the code together with the annotations to a propositional formula, and analyzing the formula for speci cation violations using a SAT-solver. If a violation is found, an execution trace exposing the error is exhibited. Code involving linked data structures with intricate invariants is particularly hard to analyze using these techniques. In this article we present TACO, a prototype tool which implements a novel, general and fully automated technique for the SAT-based analysis of JML-annotated Java sequential programs dealing with complex linked data structures. We instrument code analysis with a symmetry-breaking predicate that allows for the parallel, automated computation of tight bounds for Java elds. Experiments show that the translations to propositional formulas require signi cantly less propositional variables, leading in the experiments we have carried out to an improvement on the e ciency of the analysis of orders of magnitude, compared to the non instrumented SAT-based analysis. We show that, in somecases, our tool can uncover bugs that cannot be detected by state-of-the-art tools based on SAT-solving, model checking or SMT-solving."
Automated workarounds from Java program specifications based on SAT solving
(2018-11) Uva, Marcelo; Ponzio, Pablo; Regis, Germán; Aguirre, Nazareno; Frías, Marcelo
"The failures that bugs in software lead to can sometimes be bypassed by the so-called workarounds: when a (faulty) routine fails, alternative routines that the system offers can be used in place of the failing one, to circumvent the failure. Existing approaches to workaround-based system recovery consider workarounds that are produced from equivalent method sequences, utomatically computed from user-provided abstract models, or directly produced from user-provided equivalent sequences of operations. In this paper, we present two techniques for computing workarounds from Java code equipped with formal specifications, that improve previous approaches in two respects. First, the particular state where the failure originated is actively involved in computing workarounds, thus leading to repairs that are more state specific. Second, our techniques automatically compute workarounds on concrete program state characterizations, avoiding abstract software models and user-provided equivalences. The first technique uses SAT solving to compute a sequence of methods that is equivalent to a failing method on a specific failing state, but which can also be generalized to schemas for workaround reuse. The second technique directly exploits SAT to circumvent a failing method, building a state that mimics the (correct) behaviour of a failing routine, from a specific program state too. We perform an experimental evaluation based on case studies involving implementations of collections and a library for date arithmetic, showing that the techniques can effectively compute workarounds from complex contracts in an important number of cases, in time that makes them feasible to be used for run-time repairs. Our results also show that our state-specific workarounds enable us to produce repairs in many cases where previous workaround-based approaches are inapplicable."
Automated workarounds from Java Program specifications based on SAT solving
(2017) Uva, Marcelo; Ponzio, Pablo; Regis, Germán; Aguirre, Nazareno; Frías, Marcelo
"The failures that bugs in software lead to can sometimes be bypassed by the so called workarounds: when a (faulty) routine fails, alternative routines that the system offers can be used in place of the failing one, to circumvent the failure. Previous works have exploited this workarounds notion to automatically recover from runtime failures in some application domains. However, existing approaches that compute workarounds automatically either require the user to manually build an abstract model of the software under consideration, or to provide equivalent sequences of operations from which workarounds are computed, diminishing the automation of workaround-based system recovery. In this paper, we present two techniques that automatically compute workarounds from Java code equipped with formal specifications, avoiding abstract software models and user provided equivalences. These techniques employ SAT solving to compute workarounds on concrete program state characterizations. The first employs SAT solving to compute traditional workarounds, while the second directly exploits SAT solving to circumvent a failing method, building a state that mimics the (correct) behaviour of this failing routine. Our experiments, based on case studies involving implementations of collections and a library for date arithmetic, enable us to show that the techniques can effectively compute workarounds from complex contracts in an important number of cases, in time that makes them feasible to be used for run time repairs."
Clamper
(2019) De Ruschi, Agustín; Giannoni, Franco; Selser, Matías
"En este informe se presenta el desarrollo y diseño de un equipo que permite medir la corriente en un circuito trifásico, enviarla a un servidor y almacenar las mediciones durante días sin conexión al Gateway. Estas mediciones son importantes porque permiten realizar un análisis denominado MCSA, que permite predecir posibles modos de fallos en un equipo. Estos equipos son generalmente muy costosos y no solo el costo de su reemplazo es considerable, sino que más aún lo puede ser la interrupción del proceso que ocupa a ese equipo."
Data-driven fault diagnosis and robust control: application to PEM fuel cell systems
(2018-08) Ocampo-Martínez, Carlos; Sánchez-Peña, Ricardo; Bianchi, Fernando D.; Ingimundarson, Ari
"A data-driven methodology that includes the unfalsified control concept in the framework of fault diagnosis and isolation (FDI) and fault-tolerant control (FTC) is presented. The selection of the appropriate controller from a bank of controllers in a switching supervisory control setting is performed by using an adequate FDI outcome. By combining simultaneous online performance assessment of multiple controllers with the fault diagnosis decision from structured hypothesis tests, a diagnosis statement regarding what controller is most suitable to deal with the current (nominal or faulty) mode of the plant is obtained. Switching strategies that use the diagnosis statement are also proposed. This approach is applied to a nonlinear experimentally validated model of the breathing system of a polymer electrolyte membrane fuel cell. The results show the effectiveness of this FDI–fault-tolerant control data-driven methodology."
Evaluation of the status of rotary machines by time causal information theory quantifiers
(2017-03) Redelico, Francisco; Traversaro Varela, Francisco; Oyarzábal, Nicolás Andrés; Vilaboa, Iván; Rosso, Osvaldo A.
"In this paper several causal Information Theory quantifiers, i.e. Shannon entropy, statistical complexity and Fisher information using the Bandt and Pompe permutation probability distribution, measure are applied to describe the behavior of a rotating machine. An experiment was conducted where a rotating machine runs balanced and then, after a misalignment, runs unbalanced. All the causal Information Theory quantifiers applied are capable to distinguish between both states and grasp the corresponding transition between them. "
Fault tolerance analysis for a class of reconfigurable aerial hexarotor vehicles
(2020-08) Pose, Claudio D.; Giribet, Juan I.; Mas, Ignacio
"Several works have addressed the issue of fault tolerance in multirotors in case of a rotor total failure, particularly their ability to keep full independent control of attitude and altitude. It has been proven that to achieve this, a minimum of six rotors is needed. In this work, the performance of several standard and nonstandard hexarotor structures is analyzed, both for a nominal case (without failure) and in the case where one of the actuators is under failure (incapability to exert thrust). The performance is shown in terms of maximum rotational torque and vertical force that the vehicle can exert. The main contribution of this work is the proposal and analysis of converting these vehicles into reconfigurable ones through the addition of a minimum number of servomotors, to deal with failures and to greatly improve the maneuverability under these conditions, in order to identify the reconfigurable structure with the best performance. An experimental demonstration in an outdoor environment is shown for the proposed reconfigurable structure with best performance in case of a full rotor failure."
FLACK: Counterexample-guided fault localization for alloy models
(2021) Zheng, Guolong; Nguyen, Thanh Vu; Gutiérrez Brida, Simón; Regis, Germán; Frías, Marcelo; Aguirre, Nazareno; Bagher, Hamid
"Fault localization is a practical research topic that helps developers identify code locations that might cause bugs in a program. Most existing fault localization techniques are designed for imperative programs (e.g., C and Java) and rely on analyzing correct and incorrect executions of the program to identify suspicious statements. In this work, we introduce a fault localization approach for models written in a declarative language, where the models are not “executed,” but rather converted into a logical formula and solved using backend constraint solvers. We present FLACK, a tool that takes as input an Alloy model consisting of some violated assertion and returns a ranked list of suspicious expressions contributing to the assertion violation. The key idea is to analyze the differences between counterexamples, i.e., instances of the model that do not satisfy the assertion, and instances that do satisfy the assertion to find suspicious expressions in the input model. The experimental results show that FLACK is efficient (can handle complex, real world Alloy models with thousand lines of code within 5 seconds), accurate (can consistently rank buggy expressions in the top 1.9% of the suspicious list), and useful (can often narrow down the error to the exact location within the suspicious expressions)."
Permutation entropy based time series analysis: equalities in the input signal can lead to false conclusions
(2017-06) Zunino, Luciano; Olivares, Felipe; Scholkmann, Felix; Rosso, Osvaldo A.
"A symbolic encoding scheme, based on the ordinal relation between the amplitude of neighboring values of a given data sequence, should be implemented before estimating the permutation entropy. Consequently, equalities in the analyzed signal, i.e. repeated equal values, deserve special attention and treatment. In this work, we carefully study the effect that the presence of equalities has on permutation entropy estimated values when these ties are symbolized, as it is commonly done, according to their order of appearance. On the one hand, the analysis of computer-generated time series is initially developed to understand the incidence of repeated values on permutation entropy estimations in controlled scenarios. The presence of temporal correlations is erroneously concluded when true pseudorandom time series with low amplitude resolutions are considered. On the other hand, the analysis of real-world data is included to illustrate how the presence of a significant number of equal values can give rise to false conclusions regarding the underlying temporal structures in practical contexts."
Pronóstico de fallas en teléfonos celulares
(2010) Sabater, Florencia; Galíndez, María del Carmen
"Con el fin de mejorar los procesos, para las áreas de producto y calidad, se creó un modelo de pronóstico de fallas que utiliza información que se encuentra disponible y sin uso dentro de Motorola. Esta información esta compuesta por datos históricos, la cual se utiliza como patrón de comparación, también se utiliza la información de las quejas del call center que es el input del modelo. Éste estudio se basa fundamentalmente en comparar el comportamiento de nuevos productos, recientemente lanzados, con los existentes en el campo, de los cuales se conoce las quejas y problemas que tuvieron en el pasado. Cuando se dice que se analiza el comportamiento del producto, se hace referencia a las quejas que se registran en el call center y los reclamos recibidos identificados por un técnico en el centro de servicio autorizado por Motorola."
Reparación de programas distribuida: Stryker distribuido
(2017) Gilly, Francis Iván; Bejarano González, Fernando; Frías, Marcelo; Zemin, Luciano
"La herramienta "Stryker" implementa una técnica para reparar programas equipados con contratos. Esta técnica combina análisis dinámico (en tiempo de ejecución) con análisis estático para verificar las reparaciones candidatas y emplea un mecanismo para detectar y podar candidatos no viables aprovechando las especificaciones del programa. En este artículo se presenta "Stryker distribuido", una herramienta prototipo que implementa una mejora a la técnica de Stryker para permitir su escalamiento a múltiples computadoras. En esta nueva técnica se desarrolló un mecanismo de poda distribuida. La técnica fue evaluada para comparar su funcionamiento en múltiples computadoras utilizando un benchmark que pertenece a Stryker y que consiste en un conjunto de clases de Java con fallas. Los experimentos muestran que en general el tiempo de ejecución disminuye a medida que se aumenta la cantidad de computadoras que se utilizan. También se demostró que a mayores cantidades de fallas en el programa, se obtienen mayores reducciones en cuanto al tiempo."
SAF: sistema para el análisis y diagnóstico de fallas en líneas eléctricas de transmisión
(2004) Degl'Innocenti, Alejandro; Rossi, Bibiana D; Moreno Sánchez Capuchino, Ana María
"El proyecto consiste en desarrollar un sistema software cuyas funciones son las siguientes: identificar y diagnosticar la falla, analizar el comportamiento de las protecciones, identificar el fenómeno físico que origina la falla eléctrica".
Sistema experto para diagnóstico de fallas de transmisión eléctrica
(2003) Degl'Innocenti, Alejandro; Rossi, Bibiana D.
"El trabajo de especialidad consiste en modelar un dominio aplicando para esto la metodología IDEAL en las fases I y II de la misma sobre las siguientes etapas: identificación de la tarea, adquisición de conocimientos y conceptualización. El dominio seleccionado para este proyecto, es el análisis de fallas en líneas eléctricas de transmisión. (...) El diagnóstico es fundamental para la reposición del servicio, pero en la actualidad la mayor parte del tiempo que insume el proceso de obtención del mismo es consumido por tareas poco relevantes, tales como el tiempo requerido para convocar al especialista o el necesario para obtener los datos adquiridos por los Registradores de Eventos de las Estaciones, que es la información que documenta la falla, esto se traduce en elevados costos que como ya mencionamos se incrementan de manera proporcional al tiempo que se demora en la reposición del servicio. Por estas razones se ha considerado conveniente la confección de un Sistema Experto que permita obtener un primer diagnóstico inmediatamente después de producida una falla, que asista a especialistas y operadores del sistema."

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