Microwave and Optical Technology Letters | Year: 2017
In this letter, a novel approach to reduce frequency interference between two adjacent bands of switched LTE/3G reconfigurable antenna is proposed. The antenna has a capability to operate in LTE band (1.72–1.82 GHz) and 3G Band (1.92–2.165 GHz) by using a π slotted structure in the ground plane and PIN diodes. The length of the horizontal slot in the ground plane controls the upper frequency limit of the operation band. The vertical slots adjust the operating bandwidth at −10 dB and reduce interference between the two adjacent operating modes of the reconfigurable antenna. The fabricated antenna shows a good agreement between simulations and measurements and demonstrates the performance of the proposed approach. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1350–1353, 2017. © 2017 Wiley Periodicals, Inc.
Journal of Systems Architecture | Year: 2017
Strict periodicity constraint is of great importance since it concerns some hard real-time systems where missing deadlines leads to catastrophic situations. However, the problem of schedulability analysis for non-preemptive strictly periodic tasks on a multiprocessor platform is even more intractable than the one with the common periodicity. In order to implement such systems, designers need effective tools based on fast and near-optimal solutions. This paper presents a schedulability analysis which results mainly in a, two versions, task assignment and start-time calculation algorithm. The first one targets the harmonic task periods case while the second one targets the non-harmonic task periods case. Each version is based on a sufficient uniprocessor schedulability test. In addition, for the non-harmonic case which is the most intractable, the uniprocessor sufficient schedulability test uses the strictly periodic task utilization factor. This factor stands for the fraction of time spent to execute a task while its strict periodicity and the ones of the already scheduled tasks are met. As a result, an efficient and easily implementable scheduling algorithm is proposed which begins by assigning tasks to processors then attributes a start-time to every task in such a way that strict periodicity and deadline constraints are met. The effectiveness of the proposed scheduling algorithm, in both versions, has been shown by a performance evaluation and comparisons with an optimal and a similar suboptimal solution. © 2017 Elsevier B.V.
Microwave and Optical Technology Letters | Year: 2017
In this letter, a compact reconfigurable multiband antenna is presented. The antenna can operate in seven different modes categorized into three types, single band, dual band and triple band. The antenna is optimized to work in any band that encompasses the three standards that are, WiFi (2.4 GHz), WiMax (3.5 GHz), and WLAN (5.2 GHz). The locations of the slots as well as the size of the antenna have been optimized in order to reduce as much as possible the total area of the final prototype. For the reconfiguration four switches are integrated on the three slots to switch from one mode of operation to another. As the first validation approach, the two states “on/off” of the switch are modeled by the presence/absence of a perfect conductor (PEC). The results of measurements and simulations are presented and compared and a good agreement is established. The proposed antenna is a good candidate for multiservice and cognitive radio applications. © 2017 Wiley Periodicals, Inc.
Briand C.,Hoffmann-La Roche |
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.,Hoffmann-La Roche |
Briand C.,INSA Toulouse |
Ourari S.,Hoffmann-La Roche |
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.
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.