Sainte-Foy-lès-Lyon, France
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Seghir Z.A.,University of Khenchela | Hachouf F.,Automatic and Robotic Laboratory | Morain-Nicolier F.,CRESTIC
2013 IEEE 2nd International Conference on Image Information Processing, IEEE ICIIP 2013 | Year: 2013

In this paper, an objective assessment of image quality is considered. Principal human eyes function is to take out the region or edge information from the vision field. Based on this function, a new no-reference image quality measure is proposed. First, we identify the image edges using canny operator. Secondly, we compute the absolute difference mask. Then, the two operators are used to compute the entire metric. Experimental results show the efficiency of the suggested measure. © 2013 IEEE.

Hartert L.,CReSTIC | Nuzillard D.,CReSTIC | Nicolas J.-L.,CReSTIC | Jeannot J.-P.,CEA Cadarache Center
Communications in Computer and Information Science | Year: 2012

This article deals with the problem of change detection in the output temperature time series of the Phenix nuclear reactor core assemblies. These time series are provided by the Atomic Energy and Alternative Energies Commission (CEA). A hypothetical and theoretical blockage of an assembly cooling system could lead to a temperature rise of its nearest neighbours. To detect such a rise, first a signal preprocessing has been realized in several steps: simulation of a blockage, filtering, interpolation and re-sampling. Then, several statistical estimators have been calculated on sliding windows. The feature space has been determined based on the most discriminant parameters, including a derived third order moment. Finally, a set of classification rules has been defined to detect an assembly blockage. Thus, a statistical dynamic classification is realized online to obtain at most two classes. Results have been validated on several assemblies with different realistic perturbations. © 2012 Springer-Verlag Berlin Heidelberg.

Lazar C.,COMO Laboratory | Nuzillard D.,CReSTIC | Nowe A.,COMO Laboratory
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

A new blind source separation method for non-negative sources based on geometrical evidences of the linear mixing model is presented. We show that the proposed method is able to find the mixing matrix as well as the original sources from an observation matrix under the assumption that for every source there is at least one instance where the underlined source is active and all the others are not. One major advantage of our proposal is that the number of sources is found automatically as being the number of extreme data in a set of points. Under the assumption mentioned above, our approach outperforms two well known implementations for NNMF BSS (ALS and multiplicative update algorithms). © 2010 Springer-Verlag.

Buchoud E.,EDF | Mars J.,CNRS GIPSA Laboratory | Vrabie V.,CRESTIC | D'Urso G.,EDF | And 3 more authors.
76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 | Year: 2014

To ensure stability and durability of engineering structure in natural soil, optical fiber sensors have gained interest over last decade. In addition to conventional geophysical sensors, Brillouin spectra based sensor enables to perform distributed strain measurement. Its algorithm performs a strain measurement with a 40cm spatial sampling over several kilometers. The monitoring of engineering installations needs a centimeter spatial sampling and a better strain accuracy. Previous works highlighted that the industrialized algorithm has great limitation for the exploitation of the local information contained into Brillouin spectra. Indeed, based on its asymmetry and broadening, it is possible to estimate local Brillouin frequencies with a better strain accuracy. We propose here to apply a parametric inverse method using L-curve criterion to estimate the strain with a 5cm spatial sampling. To validate this method, a one-to-one scale experiment has been implemented by optical fiber cable at several depths. Comparing the distributed strain provided by the Brillouin based sensor and our algorithm with a reference strain sensor, the proposed algorithm successfully fulfills the combination of a 5cm spatial sampling over kilometers and a high strain accuracy.

Quang K.N.,Hanoi University of Science and Technology | Nguyen V.D.,Hanoi University of Science and Technology | Nguyer T.D.,Hanoi University of Science and Technology | Nguyer T.H.,Hanoi University of Science and Technology | Gelle G.,CReSTIC
2013 International Conference on Computing, Management and Telecommunications, ComManTel 2013 | Year: 2013

In this paper, a new cross layer design of MAC and Routing protocol for OFDMA-based Multi-hop Ad-hoc Networks is proposed. In wireless network, when a route is established, the radio resource allocation problems at MAC layer may decrease the end to end performance proportionally with the length of each route. The contention at MAC layer may causes routing protocol to respond by finding new routes and routing table updates. The cross layer design allows layers to exchange state information in order to solve the problem and obtain higher performance. The proposed cross layer design of MAC and Routing protocol based the dynamic Sub-channel Assignment Algorithm in [4] to ensure the performance of ad-hoc and multi-hop networks is significantly improved. © 2013 IEEE.

Seddiki L.,CReSTIC | Seddiki L.,CNRS Advanced Informatics Laboratory of Saint-Denis | Guelton K.,CReSTIC | Zaytoon J.,CReSTIC
IET Control Theory and Applications | Year: 2010

The authors consider the kinematic concepts of a new lower-limb rehabilitation device in closed muscular chain. The proposed control structure is based on a trajectory generator and a continuous non-linear tracking controller. The human efforts applied to this device are considered as external disturbances to the system's dynamics and as inputs to the trajectory generator and allow safe voluntary control of the system by the user. A H ∞ control structure based on a Takagi-Sugeno descriptor model is proposed to track the desired trajectories and to attenuate external disturbances. Stability conditions are given in terms of linear matrix inequalities using a fuzzy Lyapunov function. Finally, the simulation results of the proposed control structure for the new rehabilitation device during isokinetic movements illustrate the efficiency of the proposed approach. © 2010 The Institution of Engineering and Technology.

Fourati H.,CReSTIC | Fourati H.,CNRS Hubert Curien Multi-disciplinary Institute | Manamanni N.,CReSTIC | Afilal L.,CReSTIC | Handrich Y.,CNRS Hubert Curien Multi-disciplinary Institute
Biomedical Signal Processing and Control | Year: 2011

This paper concerns body attitude (orientation) estimation for free ranging animal. The main idea of the proposed approach combines a quaternion-based nonlinear observer with an Iterated Least Squares Algorithm (ILSA) and exploits measurements from Micro-Electro-Mechanical-System (MEMS) sensors as 3-axis accelerometer, 3-axis magnetometer and 3-axis gyroscope to produce attitude estimates during the entire range of the observed animal's body movements. Moreover, the proposed observer allows estimating the bias in gyroscope which is used to correct the angular velocity measurements in the attitude estimation step. Since, biologists use an index of DBA for evaluating the energy consumption of the moving animal; the resulting estimations are then used to extract the Dynamic Body Acceleration (DBA) of the animal. Note that, this work is necessary in Bio-logging science and allows monitoring aspects of animal's biology (behavior, movement, and physiology) and environments. The performance of the algorithm is theoretically proven and illustrated by an attitude estimation example. Moreover, the efficiency of the proposed approach is shown with a set of experiments through sensor measurements provided by an Inertial Measurement Unit (IMU). We have also included some comparison results with another method already applied in Bio-logging field in order to point out the improvements issued from the proposed approach. © 2010 Elsevier Ltd. All rights reserved.

Kopriva I.,Ruder Boskovic Institute | Nuzillard D.,CReSTIC
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

Estimation of pure spectral signatures, called endmembers, is a key step in hyperspectral image (HI) analysis. We propose endmembers estimation method that uses Gabor Filter Banks (GFBs) to filter HI into set of HIs with different resolutions and orientations. Afterwards, set of approximate pure pixels is identified from each filtered HI by means of directivity based criterion. Hierarchical clustering is used to estimate candidate endmembers from sets of approximate pure pixels. Final estimate of endmembers is obtained after annotation of candidate endmembers with library of pure spectral signatures. Thereby, candidate with the smallest angular deviation with respect to corresponding pure spectra is selected as endmember estimate. Proposed method is compared favorably with five endmembers estimation methods using well-understood experimental AVIRIS Cuprite Nevada dataset. © 2015 IEEE.

Ali-Bey M.,CReSTIC | Moughamir S.,CReSTIC | Manamanni N.,CReSTIC
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

This paper focuses on the calibration problem of a multi-view shooting system designed for the production of 3D content for auto-stereoscopic visualization. The considered multi-view camera is characterized by coplanar and decentered image sensors regarding to the corresponding optical axis. Based on the Faugéras and Toscani's calibration approach, a calibration method is herein proposed for the case of multi-view camera with parallel and decentered image sensors. At first, the geometrical model of the shooting system is recalled and some industrial prototypes with some shooting simulations are presented. Next, the development of the proposed calibration method is detailed. Finally, some simulation results are presented before ending with some conclusions about this work. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Couturier J.-F.,CReSTIC | Letourneur R.,CNRS Orleans Fundamental Informatics Laboratory | Liedloff M.,CNRS Orleans Fundamental Informatics Laboratory
Theoretical Computer Science | Year: 2015

A dominating set in a graph is a subset of vertices such that each vertex is either in the dominating set or adjacent to some vertex in the dominating set. It is known that graphs have at most O(1.7159n) minimal dominating sets. In this paper, we establish upper bounds on this maximum number of minimal dominating sets for split graphs, cobipartite graphs and interval graphs. For each of these graph classes, we provide an algorithm to enumerate them. For split and interval graphs, we show that the number of minimal dominating sets is at most 3n/3≈1.4423n, which is the best possible bound. This settles a conjecture by Couturier et al. (SOFSEM 2012, [1]). For cobipartite graphs, we lower the O(1.5875n) upper bound from Couturier et al. to O(1.4511n). © 2014 Elsevier B.V.

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