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Abou el Hassan, Algeria

Bouraine S.,CDTA | Fraichard T.,French Institute for Research in Computer Science and Automation | Salhi H.,Blida University
Autonomous Robots | Year: 2012

This paper addresses the problem of navigating in a provably safe manner a mobile robot with a limited field-of-view placed in a unknown dynamic environment. In such a situation, absolute motion safety (in the sense that no collision will ever take place whatever happens in the environment) is impossible to guarantee in general. It is therefore settled for a weaker level of motion safety dubbed passive motion safety: it guarantees that, if a collision takes place, the robot will be at rest. The primary contribution of this paper is the concept of Braking Inevitable Collision States (ICS), i.e. a version of the ICS corresponding to passive motion safety. Braking ICS are defined as states such that, whatever the future braking trajectory followed by the robot, a collision occurs before it is at rest. Passive motion safety is obtained by avoiding Braking ICS at all times. It is shown that Braking ICS verify properties that allow the design of an efficient Braking ICS-Checking algorithm, i.e. an algorithm that determines whether a given state is a Braking ICS or not. To validate the Braking ICS concept and demonstrate its usefulness, the Braking ICS-Checking algorithm is integrated in a reactive navigation scheme called PASSAVOID. It is formally established that PASSAVOID is provably passively safe in the sense that it is guaranteed that the robot will always stay away from Braking ICS no matter what happens in the environment. © 2011 Springer-Verlag. Source

Briand C.,Roche Holding AG | Briand C.,National Polytechnic Institute of Toulouse | Ourari S.,CDTA
RAIRO - Operations Research | Year: 2013

This paper considers the problem of scheduling n jobs on a single machine. A fixed processing time and an execution interval are associated with each job. Preemption is not allowed. The objective is to find a feasible job sequence that minimizes the number of tardy jobs. On the basis of an original mathematical integer programming formulation, this paper shows how good-quality lower and upper bounds can be computed. Numerical experiments are provided for assessing the proposed approach. © 2013 EDP Sciences, ROADEF, SMAI. Source

Briand C.,Roche Holding AG | Briand C.,INSA Toulouse | Ourari S.,Roche Holding AG | Ourari S.,INSA Toulouse | Bouzouia B.,CDTA
RAIRO - Operations Research | Year: 2010

This paper considers the problem of scheduling n jobs on a single machine. A fixed processing time and an execution interval are associated with each job. Preemption is not allowed. On the basis of analytical and numerical dominance conditions, an efficient integer linear programming formulation is proposed for this problem, aiming at minimizing the maximum lateness (Lmax). Experiments have been performed by means of a commercial solver that show that this formulation is effective on large problem instances. A comparison with the branch-and-bound procedure of Carlier is provided. © 2010 EDP Sciences, ROADEF, SMAI. Source

Hamerlain F.,CDTA
Proceedings of the 2012 UKACC International Conference on Control, CONTROL 2012 | Year: 2012

This paper investigates the trajectory tracking control problem of a nonholonomic car-like mobile robot in the presence of sliding effects. Sliding (slipping and skidding) effects are treated as disturbances and introduced into the kinematic model of the car-like using the singular perturbation approach. In order to compensate for the effects of tire slipping and skidding, a robust second order sliding mode controller is developed based on the super twisting algorithm. It is theoretically proven that for car-like vehicle subjected to sliding, the lateral-longitudinal deviations and the orientation errors can be stabilized near the origin. Simulations results show the effectiveness and the robustness of the proposed controller with respect to the sliding effects. © 2012 IEEE. Source

Ykhlef F.,CDTA | Bendaouia L.,CDTA
2012 International Conference on Signals and Electronic Systems, ICSES 2012 - The Conference Proceedings | Year: 2012

In this paper, we have performed an evaluation of several time domain features for voiced/non-voiced classification of speech signal. We have chosen in a seamless way three features: autocorrelation function (ACF), average magnitude difference function (AMDF) and weighted ACF (WACF) to form three different classifiers. Experimental results were conducted on TIMIT database in clean and noisy environments. The white noise extracted from the NOISEX92 database has been incorporated to validate the developed classifiers. We have established an overall ranking of these classifiers based on the average value of the percentage of classification accuracy (Pc). © 2012 IEEE. Source

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