Briand C.,Roche Holding AG |
Briand C.,National Polytechnic Institute of Toulouse |
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.
Briand C.,Roche Holding AG |
Briand C.,INSA Toulouse |
Ourari S.,Roche Holding AG |
Ourari S.,INSA Toulouse |
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.
Bellarbi A.,CDTA |
Domingues C.,University of Évry Val d'Essonne |
Otmane S.,University of Évry Val d'Essonne |
Benbelkacem S.,CDTA |
Proceedings of the ACM Symposium on Virtual Reality Software and Technology, VRST | Year: 2012
The introduction of virtual and mixed realities in aquatic leisure activities constitutes a technological rupture when compared with the status of related technologies. With the extension of Internet to underwater applications, the innovative character of the project becomes evident, and the impact of this development in the littoral and beach tourism may be considerable. Copyright 2012 ACM.
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.
Lopez M.B.,University of Oulu |
Boutellaa E.,CDTA |
Boutellaa E.,University of Oulu |
Hadid A.,University of Oulu |
Hadid A.,Northwestern Polytechnical University
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2016
The Kinship Face in the Wild data sets, recently published in TPAMI, are currently used as a benchmark for the evaluation of kinship verification algorithms. We recommend that these data sets are no longer used in kinship verification research unless there is a compelling reason that takes into account the nature of the images. We note that most of the image kinship pairs are cropped from the same photographs. Exploiting this cropping information, competitive but biased performance can be obtained using a simple scoring approach, taking only into account the nature of the image pairs rather than any features about kin information. To illustrate our motives, we provide classification results utilizing a simple scoring method based on the image similarity of both images of a kinship pair. Using simply the distance of the chrominance averages of the images in the Lab color space without any training or using any specific kin features, we achieve performance comparable to state-of-the-art methods. We provide the source code to prove the validity of our claims and ensure the repeatability of our experiments. © 2016 IEEE.
Ahmed A.,Control Unit |
Abdelkrim N.,Control Unit |
IFAC-PapersOnLine | Year: 2016
Simultaneous localization and mapping (SLAM) is vital for autonomous robot navigation. The robot must build a map of its environment while tracking its own motion through that map. There are many ways to approach the problem, mostly based on the sequential probabilistic approach, based around extended Kalman filter (EKF) or the Rao-Blackwellized particle filter. In order to improve the SLAM solution and to overcome some of the EKF and PF limitations, especially when the process and observation models contain uncertain parameters, we propose to use a robust approach to solve the SLAM problem based on variable structure theory. The new alternative called Smooth Variable Structure Filter SVSF is a predictor corrector estimator based on sliding mode control and estimation concepts. It has been demonstrated that the (SVSF) is stable and very robust face modeling uncertainties and noises. Visual SVSF-SLAM is implemented, validated and compared with EKF-SLAM filter. The comparison confirms the efficient and the robustness of localization and mapping using SVSF-SLAM. © 2016
Aggoune S.,CDTA |
Abid C.,Aix - Marseille University |
Fluid Dynamics and Materials Processing | Year: 2015
This paper focuses on the vortex formation effect during the application of a laser-fusion cutting technique. This industrial technique is typically associated with the ejection of a film of molten stainless steel blown offby a subsonic laminar jet of nitrogen gas used to assist the process. Without taking into account the transverse movement of the workpiece, we consider a 4 mm thick stainless steel plate. The resulting molten metal flow is assumed to be laminar, steady, viscous and incompressible. The numerical results reveal vortex structures adjacent to the walls at the entrance of the kerf, and a pair of eddies outside the kerf. Remarkably, these vortex structures can produce a separation point in the molten film, and thereby they can affect the surface quality of the processed material. The problem is investigated in the frameworkof a numerical technique available in the Fluent software, based on a volume of fluid (VOF) surface-tracking strategy and the enthalpy method to account for material solidification or melting. © 2015 Tech Science Press.
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.
Aggoune S.,CDTA |
Defect and Diffusion Forum | Year: 2014
We consider in the present work the fusion laser cutting of stainless steel sheets under a nitrogen laminar gas jet. The molten metal is treated as a laminar and steady viscous incompressible fluid. The mathematical model describing our problem is set in terms of Navier-Stokes equations, solved numerically using the finite differences method, where the effect of the gas jet velocity on the molten boundary layer is considered. The generated shear stress occurring on the gas-liquid interface and its contribution in the momentum is carried out, and it is found that when the skin friction and the shear stress decrease, the thickness and the velocity at the edge of the molten boundary layer increase along the kerf surface. The layer thickness reduces when the assisting gas velocity is increased.© (2014) Trans Tech Publications, Switzerland.
Ykhlef F.,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.