References of "Boutaayamou, Mohamed"
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See detailDesign and fabrication of an electrode array sensor for probing the electric potential distribution at the mesoscopic scale in antistatic felts
Boutaayamou, Mohamed ULg; Lemaire, Philippe; Vanderheyden, Benoît ULg et al

in Measurement Science and Technology (2014), 25

We present an original voltage probe design for measuring the electric potential distribution at the mesoscopic scale (i.e., 1 mm–1 cm) in antistatic felts. The felts are composed of a mixture of non ... [more ▼]

We present an original voltage probe design for measuring the electric potential distribution at the mesoscopic scale (i.e., 1 mm–1 cm) in antistatic felts. The felts are composed of a mixture of non-conductive and metallic fibers and exhibit complex nonlinear electric behavior—including possibly nonlinearity and hysteresis effects—which may be due to localized electrical or electromechanical phenomena. The sensor consists of an array of 8 × 9 needle electrodes (phgr 160 µm at the shaft and less than phgr 50 µm toward the apex), which are mechanically maintained at fixed relative positions while their tips are inserted inside the fabric of the sample. The interelectrode distance is 1.5 mm and the overall active area is 12 × 12 mm². The electrical insulation resistance for nearest neighbor pairs of electrodes was found to be larger than 860 GΩ, thus making the sensor suitable for measuring antistatic felts with an electric resistance that typically does not exceed a few GΩ. The sensor was successfully used for measuring the distribution of the electric potential in a polyester fabric subjected to voltages of up to 6.2 kV, and in a sample containing 2% in weight of metallic fibers, demonstrating the presence of irreversible changes in that felt sample (i.e., with conductive fibers) at high voltages. It is concluded that the developed probe voltage is a promising technique that could be used for the assessment of the conduction mechanisms in the antistatic materials at the mesoscopic scale. [less ▲]

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See detail3D analysis of gait using accelerometer measurements
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Stamatakis, Julien et al

Scientific conference (2013, November 07)

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See detailValidation of an accelerometer-based approach to quantify gait events
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Stamatakis, Julien et al

Poster (2013, June)

Researchers rarely provide solid performance and validation information about their acceleometer-based approaches to human gait analysis. We present here a novel signal processing and analysis algorithm ... [more ▼]

Researchers rarely provide solid performance and validation information about their acceleometer-based approaches to human gait analysis. We present here a novel signal processing and analysis algorithm that automatically extracts four consecutive fundamental events of walking: heel strike (HS), toe strike (TS), heel off (HO), and toe off (TO). In addition, we validate this accelerometer-based technique by comparing these extracted gait events with those obtained by a kinematic 3D analysis system and a force plate, used as gold standards. [less ▲]

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See detailValidated Extraction of Gait Events from 3D Accelerometer Recordings
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Stamatakis, Julien et al

in IEEE International Conference on 3D Imaging (IC3D) (2012, December)

This work is part of a project that deals with the three-dimensional (3D) analysis of normal and pathological gaits based on a newly developed system for clinical applications, using low-cost wireless ... [more ▼]

This work is part of a project that deals with the three-dimensional (3D) analysis of normal and pathological gaits based on a newly developed system for clinical applications, using low-cost wireless accelerometers and a signal processing algorithm. This system automatically extracts relevant gait events such as the heel strikes (HS) and the toe-offs (TO), which characterize the stance and the swing phases of walking. The performances of the low-cost accelerometer hardware and related algorithm have been compared to those obtained by a kinematic 3D analysis system and a force plate, used as gold standard methods. The HS and TO times obtained from the gait data of 7 healthy volunteers (147 trials) have been found to be (mean ± standard deviation) 0.42±7.92 ms and 3.11±10.08 ms later than those determined by the force plate, respectively. The experimental results demonstrate that the new hardware and associated algorithm constitute an effective low-cost gait analysis system, which could thus be used for the assessment of mobility in routine clinical practice. [less ▲]

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See detail3D Analysis of Normal and Pathological Gait Based on Low-Cost Wireless Accelerometers
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Bruls, Olivier ULg et al

in URSI Benelux Forum 2012 “Antennas: multiple designs, multiple applications” (2012)

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological ... [more ▼]

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological gait. [less ▲]

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See detailStudy of Conduction Mechanisms in Antistatic Felts at the Mesoscopic Scale
Boutaayamou, Mohamed ULg; Léonard, Angélique ULg; Vanderheyden, Benoît ULg et al

in International Symposium on New Frontiers in Fiber Materials Science; Conference Proceedings (2011, October 11)

This work is part of a project that deals with the optimization of the quantity and the nature of conductive fibers in antistatic felts used for filtering and sieving powders. Our research concerns the ... [more ▼]

This work is part of a project that deals with the optimization of the quantity and the nature of conductive fibers in antistatic felts used for filtering and sieving powders. Our research concerns the electrical properties at the mesoscopic scale. It aims at determining the conduction mechanisms and the distribution of the electric potential at the scale of the distance between the conductive fibers. In this paper, current-voltage (I-V) measurement results are presented and discussed. X-ray microtomography is used to obtain the geometry of the conductive fibers inside the felts before and after these I-V tests. The studied textile material is based on polyester fibers and stainless steel conductive fibers. [less ▲]

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See detailMéthode de Perturbation pour la Modélisation par Éléments Finis des Systèmes Électrostatiques en Mouvement - Application aux MEMS Électrostatiques
Boutaayamou, Mohamed ULg

Doctoral thesis (2009)

La modélisation par éléments finis des conducteurs en mouvement nécessite généralement des calculs successifs et le remalliage de certaines régions. Une modélisation 3D de géométries complexes par les ... [more ▼]

La modélisation par éléments finis des conducteurs en mouvement nécessite généralement des calculs successifs et le remalliage de certaines régions. Une modélisation 3D de géométries complexes par les techniques classiques nécessite dès lors de gros efforts en terme de temps de calcul. Dans cette thèse, une méthode originale basée sur une approche par sous-problèmes, appelée méthode de perturbation, a été développée. Utilisant la méthode des éléments finis, cette technique consiste à subdiviser un problème entier en sous-problèmes. La complexité du problème initial est par conséquent diminuée en ne se concentrant que sur les zones les plus pertinentes. Appliquée aux systèmes en mouvement, la méthode de perturbation permet d'exploiter les résolutions antérieures au lieu d'effectuer un nouveau calcul pour chaque position. L'analyse par la méthode de perturbation des microsystèmes électromécaniques (MEMS) électrostatiques comprenant des parties en déplacement ou en déformation est en outre considérée dans ce travail. Il est notamment question de démontrer l'implication naturelle de cette approche pour des simulations plus efficaces et plus précises des MEMS électrostatiques. [less ▲]

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See detailElectrostatic Analysis of Moving Conductors Using a Perturbation Finite Element Method
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in IEEE Transactions on Magnetics (2009), 45(3), 1004-1007

This paper deals with the analysis of electrostatic problems involving moving devices by means of a perturbation finite element method. A reference problem without any moving parts is first solved and ... [more ▼]

This paper deals with the analysis of electrostatic problems involving moving devices by means of a perturbation finite element method. A reference problem without any moving parts is first solved and gives the source for a sequence of perturbation problems in subdomains restricted to the neighborhood of these parts. The source accounts for all the previous calculations for preceding positions what increases the efficiency of the simulations. This proposed approach also improves the computation accuracy and decreases the complexity of the analysis of moving conductors thanks to the use of independent and adaptively refined meshes. [less ▲]

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See detailAn iterative finite element perturbation method for computing electrostatic field distortions
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in IEEE Transactions on Magnetics (2008), 44(6), 746-749

A finite element perturbation method is developed for computing electrostatic field distortions and the ensuing charges and forces on moving conductive regions subjected to fixed potentials. It is based ... [more ▼]

A finite element perturbation method is developed for computing electrostatic field distortions and the ensuing charges and forces on moving conductive regions subjected to fixed potentials. It is based on the subsequent solution of an unperturbed problem in a complete domain, where conductive regions have been extracted, and of perturbation problems in subdomains restricted to the surroundings of the added conductive regions. The solution of the unperturbed problem serves as source (with a very reduced support) for the perturbation subproblems. For every new position of the conductors, the solution of the unperturbed problem does not vary and is thus reused; only the perturbation subproblems have to be solved. Further, this approach allows for the use of independent and well-adapted meshes. An iterative procedure is required if the conductive regions are close to the sources. [less ▲]

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See detailElectrostatic analysis of moving conductors using a finite element perturbation method
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Proceedings of the 13th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2008) (2008, May)

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See detailA perturbation method for the 3D finite element modeling of electrostatically driven MEMS
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Sensors (2008), 8(2), 994-1003

In this paper, a finite element (FE) procedure for modeling electrostatically actuated MEMS is presented. It concerns a perturbation method for computing electrostatic field distortions due to moving ... [more ▼]

In this paper, a finite element (FE) procedure for modeling electrostatically actuated MEMS is presented. It concerns a perturbation method for computing electrostatic field distortions due to moving conductors. The computation is split in two steps. First, an unperturbed problem (in the absence of certain conductors) is solved with the conventional FE method in the complete domain. Second, a perturbation problem is solved in a reduced region with an additional conductor using the solution of the unperturbed problem as a source. When the perturbing region is close to the original source field, an iterative computation may be required. The developed procedure offers the advantage of solving sub-problems in reduced domains and consequently of benefiting from different problem-adapted meshes. This approach allows for computational efficiency by decreasing the size of the problem. [less ▲]

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See detailFinite element modeling of electrostatic MEMS including the impact of fringing field effects on forces
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Sensor Letters (2008), 6(1), 115-120

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking fringing fields into account is crucial for an accurate ... [more ▼]

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking fringing fields into account is crucial for an accurate computation of the electrostatic forces. In this work, the finite element method is applied for modeling electrostatic actuators. The electrostatic force distribution is obtained by locally applying the virtual work method. A micro-beam and a comb drive are considered as test cases. The impact of the fringing field effects on the accurate computation of electrostatic forces and capacitances is shown through 2D and 3D parametric studies. [less ▲]

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See detailA Perturbation Finite Element Method for Modeling Electrostatic MEMS without Remeshing
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Proceedings of the 9th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems (EuroSimE2008) (2008)

This paper deals with the coupled electrostatic- mechanical analysis of electrostatically actuated MEMS. An iterative perturbation procedure in conjunction with the finite element method is used to solve ... [more ▼]

This paper deals with the coupled electrostatic- mechanical analysis of electrostatically actuated MEMS. An iterative perturbation procedure in conjunction with the finite element method is used to solve the coupled problem without the need of remeshing the whole electric domain. The method offers the advantage of overcoming degenerated finite elements in the mesh of some electric regions where the deflection of the MEMS moving parts is critical. The actuation of such systems is achieved by applying either an electric voltage or a global charge. [less ▲]

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See detailAn Iterative Finite Element Perturbation Method for Computing Electrostatic Field Distortions
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Proceedings of 16th Conference on the Computation of Electromagnetic Fields (COMPUMAG2007) (2007, June)

A finite element (FE) perturbation method for computing electrostatic field distortions due to moving conductors is presented. First, an unperturbed problem (in the absence of conductors) is solved with ... [more ▼]

A finite element (FE) perturbation method for computing electrostatic field distortions due to moving conductors is presented. First, an unperturbed problem (in the absence of conductors) is solved with the conventional FE method in the complete domain. Then, a perturbed problem is computed in a reduced region using the solution of the unperturbed problem as a source field. When the source is close to the perturbing regions, an iterative computation may be required. The developed procedure allows for solving sub-problems in reduced domains with independent problem-adapted meshes. [less ▲]

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See detailA Perturbation Method for the 3D Finite Element Modeling of Electrostaticaly Driven MEMS
Boutaayamou, Mohamed ULg; V Sabariego, Ruth ULg; Dular, Patrick ULg

in Proceedings of the 8th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems (2007, April)

In this paper, a finite element (FE) procedure for modeling electrostatically actuated MEMS is presented. It concerns a perturbation method for computing electrostatic field distortions due to moving ... [more ▼]

In this paper, a finite element (FE) procedure for modeling electrostatically actuated MEMS is presented. It concerns a perturbation method for computing electrostatic field distortions due to moving conductors. The computation is split in two steps. First, an unperturbed problem (in the absence of certain conductors) is solved with the conventional FE method in the complete domain. Second, a perturbation problem is solved in a reduced region with an additional conductor using the solution of the unperturbed problem as a source. When the perturbing regions are close to the original source field, an iterative computation may be required. The developed procedure offers the advantage of solving sub-problems in reduced domains and consequently of benefiting from different problem-adapted meshes. This approach allows for computational efficiency by decreasing the size of the problem. [less ▲]

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See detailFinite element modelling of electrostatic MEMS including the impact of fringing field effects on forces
Boutaayamou, Mohamed ULg; Nair, Harish; V Sabariego, Ruth ULg et al

in Proceedings of the 7th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems (EuroSimE2006) (2006)

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking the fringing fields into account is crucial for an accurate ... [more ▼]

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking the fringing fields into account is crucial for an accurate computation of the electrostatic forces. In this work, the finite element method is applied for modeling electrostatic actuators. The electrostatic force distribution is obtained by locally applying the virtual work method. A micro-beam and a comb drive are considered as test cases. The impact of the fringing field effects on the accuracy of electrostatic forces is shown through 2D and 3D parametric studies. [less ▲]

Detailed reference viewed: 54 (18 ULg)