References of "Nejjari, Fatiha"
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See detailOn-line model-based fault detection and isolation for PEM fuel cell stack systems
Rosich, Albert UL; Sarrate, Ramon; Nejjari, Fatiha

in Applied Mathematical Modelling (in press)

Efficient and reliable operation of Polymer Electrolyte Membrane (PEM) fuel cells are key requirements for their successful commercialization and application. The use of diagnostic techniques enables the ... [more ▼]

Efficient and reliable operation of Polymer Electrolyte Membrane (PEM) fuel cells are key requirements for their successful commercialization and application. The use of diagnostic techniques enables the achievement of these requirements. This paper focuses on model-based fault detection and isolation (FDI) for PEM fuel cell stack systems. The work consists in designing and selecting a subset of consistency relations such that a set of predefined faults can be detected and isolated. Despite a nonlinear model of the PEM fuel cell stack system will be used, consistency relations that are easily implemented by a variable back substitution method will be selected. The paper also shows the significance of structural models to solve diagnosis issues in complex systems. [less ▲]

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See detailModel-based Optimal Sensor Placement Approaches to Fuel Cell Stack System Fault Diagnosis
Sarrate, Ramon; Nejjari, Fatiha; Rosich, Albert UL

in Fault Detection, Supervision and Safety of Technical Processes, Volume# 8 | Part# 1 (2012)

The problem of optimal sensor placement for FDI consists in determining the set of sensors that minimizes a pre-defined cost function satisfying at the same time a pre-established set of FDI ... [more ▼]

The problem of optimal sensor placement for FDI consists in determining the set of sensors that minimizes a pre-defined cost function satisfying at the same time a pre-established set of FDI specifications for a given set of faults. This paper recalls three model-based optimal sensor location approaches: an Incremental search, a Heuristic search and a Binary Integer Linear Programming (BILP) formulation. The main contribution of this paper is a comparative study that addresses efficiency, flexibility and other issues. The performance of the approaches is demonstrated by an application to a fuel cell stack system. [less ▲]

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See detailOptimal Sensor Placement for Leakage Detection and Isolation in Water Distribution Networks
Rosich, Albert UL; Sarrate, Ramon; Nejjari, Fatiha

in Fault Detection, Supervision and Safety of Technical Processes, Volume# 8 | Part# 1 (2012)

In this paper, the problem of leakage detection and isolation in water distribution networks is addressed applying an optimal sensor placement methodology. The chosen technique is based on structural ... [more ▼]

In this paper, the problem of leakage detection and isolation in water distribution networks is addressed applying an optimal sensor placement methodology. The chosen technique is based on structural models and thus it is suitable to handle non-linear and large scale systems. A drawback of this technique arises when costs are assigned uniformly. A main contribution of this paper is the proposal of an iterative methodology that focuses on identifying essential sensors which ultimately leads to an improvement of the optimal search efficiency. The algorithm presented in this work is successfully applied to a District Metered Area (DMA) in the Barcelona water distribution network. [less ▲]

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See detailSensor Placement for Fault Diagnosis Performance Maximization in Distribution Networks
Sarrate, Ramon; Nejjari, Fatiha; Rosich, Albert UL

in Control & Automation (MED), 2012 20th Mediterranean Conference on (2012)

The success of any diagnosis strategy critically depends on the sensors measuring process variables. This paper presents a strategy based on diagnosability maximization for optimally locating sensors in ... [more ▼]

The success of any diagnosis strategy critically depends on the sensors measuring process variables. This paper presents a strategy based on diagnosability maximization for optimally locating sensors in distribution networks. The goal is to characterize and determine the set of sensors that guarantees a maximum degree of diagnosability taking into account a given sensor configuration cardinality constraint. The strategy is based on the structural model of the system under consideration. Structural analysis is a powerful tool for determining diagnosis possibilities and evaluating whether the number and the location of sensors are adequate in order to meet some diagnosis specifications. The proposed approach is successfully applied to leakage detection in a Drinking Water Distribution Network. [less ▲]

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See detailSensor Placement for Fault Diagnosis Performance Maximization under Budgetary Constraints
Sarrate, Ramon; Nejjari, Fatiha; Rosich, Albert UL

in 2nd International Conference on Systems and Control (2012)

This paper presents a strategy based on fault diagnosability maximization to optimally locate sensors in complex systems. The goal is to characterize and determine a sensor configuration that guarantees a ... [more ▼]

This paper presents a strategy based on fault diagnosability maximization to optimally locate sensors in complex systems. The goal is to characterize and determine a sensor configuration that guarantees a maximum degree of diagnosability and does not exceed a maximum sensor configuration cost. The strategy is based on the structural system model. Structural analysis is a powerful tool for dealing with complex nonlinear systems. The proposed approach is successfully applied to a Fuel Cell Stack System. [less ▲]

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See detailFault Diagnosis Based On Causal Computations
Rosich, Albert UL; Frisk, Erik; Åslund, Jan et al

in IEEE Transactions on Systems, Man & Cybernetics : Part A (2011), 42(2), 371-381

This paper focuses on residual generation for model-based fault diagnosis. Specifically, a methodology to derive residual generators when nonlinear equations are present in the model is developed. A main ... [more ▼]

This paper focuses on residual generation for model-based fault diagnosis. Specifically, a methodology to derive residual generators when nonlinear equations are present in the model is developed. A main result is the characterization of computation sequences that are particularly easy to implement as residual generators and that take causal information into account. An efficient algorithm, based on the model structure only, which finds all such computation sequences, is derived. Furthermore, fault detectability and isolability performances depend on the sensor configuration. Therefore, another contribution is an algorithm, also based on the model structure, that places sensors with respect to the class of residual generators that take causal information into account. The algorithms are evaluated on a complex highly nonlinear model of a fuel cell stack system. A number of residual generators that are, by construction, easy to implement are computed and provide full diagnosability performance predicted by the model. [less ▲]

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See detailOptimal Sensor Placement For Fuel Cell System Diagnosis using BILP Formulation
Nejjari, Fatiha; Sarrate, Ramon; Rosich, Albert UL

in Control & Automation (MED), 2010 18th Mediterranean Conference on (2010)

This paper presents the application of a new methodology for Fault Detection and Isolation (FDI) to a Fuel Cell System. The work is devoted to find an optimal set of sensors for model-based FDI. The ... [more ▼]

This paper presents the application of a new methodology for Fault Detection and Isolation (FDI) to a Fuel Cell System. The work is devoted to find an optimal set of sensors for model-based FDI. The novelty is that binary integer linear programming (BILP) is used in the optimization formulation, leading to a reformulation of the detectability and isolability specifications as linear inequality constraints. The approach has been successfully applied to a Fuel Cell System. [less ▲]

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See detailFuel Cell System Diagnosis based on a Causal Structural Model
Rosich, Albert UL; Nejjari, Fatiha; Sarrate, Ramon

in Fault Detection, Supervision and Safety of Technical Processes (2009)

In this work, a diagnosis system is developed and applied to a fuel cell stack system. The paper shows the significance of structural models to solve diagnosis issues in large scale systems. The diagnosis ... [more ▼]

In this work, a diagnosis system is developed and applied to a fuel cell stack system. The paper shows the significance of structural models to solve diagnosis issues in large scale systems. The diagnosis system based on residual generation by means of the computation of causal MSO sets (Minimal Structural Overdetermined) is capable of detecting and isolating faults in the fuel cell system. [less ▲]

Detailed reference viewed: 54 (3 UL)
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See detailSensor Placement for Fault Diagnosis Based On Causal Computations
Rosich, Albert UL; Frisk, Erik; Åslund, Jan et al

in Fault Detection, Supervision and Safety of Technical Processes (2009)

This work develops a methodology to solve the sensor placement problem for fault detection and isolation. The proposed methodology is suitable to handle highly non-linear and large scale systems since it ... [more ▼]

This work develops a methodology to solve the sensor placement problem for fault detection and isolation. The proposed methodology is suitable to handle highly non-linear and large scale systems since it is based on structural models. Furthermore, causality is assigned in those variable-equation relations that the variable can be computed from the equation in order to guarantee the computability of the unknown variables in the residual generation design. Finally, the developed methodology is applied on an air compressor model. [less ▲]

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See detailOptimal Sensor Placement for FDI using Binary Integer Linear Programming
Rosich, Albert UL; Sarrate, Ramon; Nejjari, Fatiha

in 20th International Workshop on Principles of Diagnosis (2009)

This work is devoted to find an optimal set of sensors for model-based FDI. The novelty is that linary integer linear programming is used in the optimization problem, leading to a formulation of the ... [more ▼]

This work is devoted to find an optimal set of sensors for model-based FDI. The novelty is that linary integer linear programming is used in the optimization problem, leading to a formulation of the detectability and isolability specifications as linear inequality constraints. Furthermore, a very detailed system model is not needed since the methodology handles structural models. The approach has been successfully applied to a two-tank system, as an illustrative example. [less ▲]

Detailed reference viewed: 85 (3 UL)