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Tahri O.,INSA Val de Loire | Boutat D.,INSA Val de Loire | Mezouar Y.,CNRS Pascal Institute
IEEE Transactions on Robotics | Year: 2017

Conventional active incremental structure from motion (ISfM) schemes require a precise knowledge of the linear and angular velocities of the vision system to compute the three-dimensional structure of the observed scene. Furthermore, they are generally coupled and nonlinear, which makes the reconstruction inaccurate. In this paper, we present a novel active ISfM scheme to overcome these difficulties. It relies on two appropriate transformations: the first one allows efficient decoupling of the nonlinear model, whereas the second one transforms the decoupled model into the Brunovsky’s linear form. We then show that a Luenberger’s observer can be designed to estimate the unavailable states, making our scheme globally asymptotically convergent and robust to noise on measurements. We present simulated and experimental results to illustrate the performance of the described methodology. IEEE


Ladjal H.,University Claude Bernard Lyon 1 | Hanus J.-L.,INSA Val de Loire | Ferreira A.,INSA Val de Loire
IEEE Transactions on Biomedical Engineering | Year: 2013

To facilitate training of biological cell injection operations, we are developing an interactive virtual environment to simulate needle insertion into biological cells. This paper presents methodologies for dynamic modeling, visual/haptic display, and model validation of cell injection. We first investigate the challenging issues in the modeling of the biomechanical properties of living cells. We propose two dynamic models to simulate cell deformation and puncture. The first approach is based on the assumptions that the mechanical response of living cells is mainly determined by the cytoskeleton and that the cytoskeleton is organized as a tensegrity structure including microfilaments, microtubules, and intermediate filaments. Equivalent microtubules struts are represented with a linear mass-tensor finite-element model and equivalent microfilaments and intermediate filaments with viscoelastic Kelvin-Voigt elements. The second modeling method assumes the overall cell as an homogeneous hyperelastic model (St, Venant-Kirchhoff). Both graphic and haptic rendering are provided in real time to the operator through a 3-D virtual environment. Simulated responses are compared to experimental data to show the effectiveness of the proposed physically based model. © 1964-2012 IEEE.


Arcese L.,University of Orléans | Fruchard M.,University of Orléans | Ferreira A.,INSA Val de Loire
IEEE Transactions on Biomedical Engineering | Year: 2012

This paper deals with the benefits of using a nonlinear model-based approach for controlling magnetically guided therapeutic microrobots in the cardiovascular system. Such robots used for minimally invasive interventions consist of a polymer binded aggregate of nanosized ferromagnetic particles functionalized by drug-conjugated micelles. The proposed modeling addresses wall effects (blood velocity in minor and major vessels' bifurcations, pulsatile blood flow and vessel walls, and effect of robot-to-vessel diameter ratio), wall interactions (contact, van der Waals, electrostatic, and steric forces), non-Newtonian behavior of blood, and different driving designs as well. Despite nonlinear and thorough, the resulting model can both be exploited to improve the targeting ability and be controlled in closed-loop using nonlinear control theory tools. In particular, we infer from the model an optimization of both the designs and the reference trajectory to minimize the control efforts. Efficiency and robustness to noise and model parameter's uncertainties are then illustrated through simulations results for a bead pulled robot of radius 250 μm in a small artery. © 2006 IEEE.


Joy J.,INSA Val de Loire
AI and Society | Year: 2012

This article presents a sample of references issuing directly from the existing NMSAT database. The method employed-that of systematically probing the database-reveals forms of sonification, but also hypothetical premises of sonification, covering the period from ancient times to the beginning of the twentieth century. The following are some of the categories of sonification that have emerged as a result of this search: Natural phenomenon & meteorology to sound (autophones); Image to sound; Text & communication to sound; Human & machine activities to sound (auditing); Localisation to sound (sonar); Architecture & geometry & abstract proportions to sound (scalization, transcription, & spatialization); Energy to sound; Human body to sound; Distance to sound (distance listening); Movement to sound (holophony, kynophony); and Interpreted observations to sound (naturalist music, transpositions & analogies, paraphrasing). The search also uncovered other principals and practices in the vicinity of sonification including: audification, auditing, auscultation, auralization, soniculation, transduction, mapping, earcons, auditory icons, sympathy, echometry, etc. It has been decided to summarise the results of « What NMSAT Says About Sonification » in this special issue of AI&Society, access to the unabridged version of article is available here: http://www. locusonus. org/sonification/. © 2011 Springer-Verlag London Limited.


Batailly A.,McGill University | Magnain B.,INSA Val de Loire | Chevaugeon N.,École Centrale Nantes
Computational Mechanics | Year: 2013

The numerical simulation of contact problems is still a delicate matter especially when large transformations are involved. In that case, relative large slidings can occur between contact surfaces and the discretization error induced by usual finite elements may not be satisfactory. In particular, usual elements lead to a facetization of the contact surface, meaning an unavoidable discontinuity of the normal vector to this surface. Uncertainty over the precision of the results, irregularity of the displacement of the contact nodes and even numerical oscillations of contact reaction force may result of such discontinuity. Among the existing methods for tackling such issue, one may consider mortar elements (Fischer and Wriggers, Comput Methods Appl Mech Eng 195:5020-5036, 2006; McDevitt and Laursen, Int J Numer Methods Eng 48:1525-1547, 2000; Puso and Laursen, Comput Methods Appl Mech Eng 93:601-629, 2004), smoothing of the contact surfaces with additional geometrical entity (B-splines or NURBS) (Belytschko et al., Int J Numer Methods Eng 55:101-125, 2002; Kikuchi, Penalty/finite element approximations of a class of unilateral contact problems. Penalty method and finite element method, ASME, New York, 1982; Legrand, Modèles de prediction de l'interaction rotor/stator dans un moteur d'avion Thèse de doctorat. PhD thesis, École Centrale de Nantes, Nantes, 2005; Muñoz, Comput Methods Appl Mech Eng 197:979-993, 2008; Wriggers and Krstulovic-Opara, J Appl Math Mech (ZAMM) 80:77-80, 2000) and, the use of isogeometric analysis (Temizer et al., Comput Methods Appl Mech Eng 200:1100-1112, 2011; Hughes et al., Comput Methods Appl Mech Eng 194:4135-4195, 2005; de Lorenzis et al., Int J Numer Meth Eng, in press, 2011). In the present paper, we focus on these last two methods which are combined with a finite element code using the bi-potential method for contact management (Feng et al., Comput Mech 36:375-383, 2005). A comparative study focusing on the pros and cons of each method regarding geometrical precision and numerical stability for contact solution is proposed. The scope of this study is limited to 2D contact problems for which we consider several types of finite elements. Test cases are given in order to illustrate this comparative study. © 2012 Springer-Verlag.


Tihay V.,Prisme Institute | Tihay V.,CNRS Environmental Sciences | Gillard P.,Prisme Institute | Blanc D.,INSA Val de Loire
Journal of Hazardous Materials | Year: 2012

The breakdown and the laser-induced spark ignition of acetone-air mixtures were experimentally studied using a nanosecond pulse at 1064. nm from a Q-switched Nd:YAG laser. The breakdown was first characterized for different mixtures with acetone and air. This part of the work highlighted the wide variation in the energy absorbed by the plasma during a breakdown. We also demonstrated that the presence of acetone in air tends to reduce the energy required to obtain a breakdown. Next, the ignition of acetone-air mixtures in the equivalence ratio range 0.9-2.4 was investigated. The probabilities of ignition were calculated in function to the laser energy. However, according to the variability of energy absorption by the plasma, we preferred to present the result according to the energy absorbed by the plasma. The minimum ignition energies were also provided. The minimum ignition energy was obtained for an equivalence ratio of 1.6 and an absorbed energy of 1.15. mJ. Finally the characteristics of the plasma (absorption coefficient and kernel temperature) were calculated for the experiments corresponding to minimum ignition energies. © 2012 Elsevier B.V.


Boutat D.,INSA Val de Loire | Boutat-Baddas L.,Nancy Research Center for Automatic Control | Darouach M.,Nancy Research Center for Automatic Control
Systems and Control Letters | Year: 2012

This paper presents a new observability normal form for discrete-time nonlinear systems. This form enables us to design a reduced-order observer. Necessary and sufficient geometrical conditions for the existence of a coordinate change to transform a discrete-time nonlinear system into such normal form are given. An illustrative example is given to show the effectiveness of our approach. © 2012 Elsevier B.V. All rights reserved.


Hamdi M.,INSA Val de Loire | Ferreira A.,INSA Val de Loire
IEEE Transactions on Robotics | Year: 2014

This study proposes molecular dynamics simulations used to derive guidelines for the design of the superparamagnetic nanocapsules (spherical-like or rod-like) dedicated to cross the brain-blood barrier (BBB) by magnetic forces. We focus our study on capillaries that have opened fenestrations when the integrity of the endothelial barrier is perturbed by tumors. We identified three different categories of governing parameters: geometrical (radius and length of nanocapsules), biophysical (ligand-to-receptor surface density ratio, nonspecific interaction parameters) and biological (ligand/receptor binding affinity). The main novelty of our study is to carry out computational simulations to determine design criteria - the size, charge, and shape of various magnetic nanocapsules (spherical and rod-shaped nanocapsules) - that optimize their penetration into the BBB. Finally, the simulation results show that the superparamagnetic nanorobotic capsules were able to cross the endothelial barrier by using magnetic forces compatible with medical constraints. © 2013 IEEE.


Smari W.W.,Ball Corporation | Clemente P.,INSA Val de Loire | Lalande J.-F.,INSA Val de Loire
Future Generation Computer Systems | Year: 2014

Many efforts in the area of computer security have been drawn to attribute-based access control (ABAC). Compared to other adopted models, ABAC provides more granularity, scalability, and flexibility. This makes it a valuable access control system candidate for securing platforms and environments used for coordination and cooperation among organizations and communities, especially over open networks such as the Internet. On the other hand, the basic ABAC model lacks provisions for context, trust and privacy issues, all of which are becoming increasingly critical, particularly in high performance distributed collaboration environments. This paper presents an extended access control model based on attributes associated with objects and subjects. It incorporates trust and privacy issues in order to make access control decisions sensitive to the cross-organizational collaboration context. Several aspects of the proposed model are implemented and illustrated by a case study that shows realistic ABAC policies in the domain of distributed multiple organizations crisis management systems. Furthermore, the paper shows a collaborative graphical tool that enables the actors in the emergency management system to make better decisions. The prototype shows how it guarantees the privacy of object's attributes, taking into account the trust of the subjects. This tool incorporates a decision engine that relies on attribute based policies and dynamic trust and privacy evaluation. The resulting platform demonstrates the integration of the ABAC model, the evolving context, and the attributes of actors and resources. © 2013 Elsevier B.V. All rights reserved.


Arcese L.,University of Reims Champagne Ardenne | Fruchard M.,University of Orléans | Ferreira A.,INSA Val de Loire
IEEE Transactions on Robotics | Year: 2013

This paper discusses the control design of a magnetically guided microrobotic system in blood vessels to perform minimally invasive medical procedures. Such microrobots consist of a polymer-bonded aggregate of nanosized ferromagnetic particles and a possible payload that can be propelled by the gradient coils of a magnetic device. A fine modeling is developed and used to define an optimal trajectory which minimizes the control efforts. We then synthesize an adaptive backstepping law that ensures a Lyapunov stable and fine tracking, despite modeling errors, and estimates some key uncertain parameters. As the controller synthesis uses the microrobot unmeasured velocity, the design of a high-gain observer is also addressed. Simulations and experiment illustrate the robustness to both noise measurement and some uncertain physiological parameters for a 250 μm radius microrobot that navigates in a fluidic environment. © 2004-2012 IEEE.

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