PRISME laboratory

Saint-Léonard-de-Noblat, France

PRISME laboratory

Saint-Léonard-de-Noblat, France
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Zerdzicki K.,Technical University of Gdansk | Klosowski P.,Technical University of Gdansk | Woznica K.,INSA Val de Loire | Woznica K.,PRISME Laboratory
Shell Structures: Theory and Applications - Proceedings of the 10th SSTA 2013 Conference | Year: 2014

The study of inelastic properties of the technical fabric Valmex used for 20 years as the roof structure of the Forest Opera in Sopot (Poland) is presented. Uniaxial tensile laboratory tests with constant strain rate have been conducted and analysed. Parameters of the Bodner-Partom constitutive model have been identified and verified by numerical simulations.Two approaches to parameter identification have been proposed: one (simplified) for laboratory analysis and the other (extended) for numerical calculations of the shell structures covered with the technical fabrics. Both approaches have proved their correctness in the FEM analysis.

Bettamer A.,University of Benghazi | Allaoui S.,Prisme Laboratory | Hambli R.,Prisme Laboratory
Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization | Year: 2017

An accurate measuring tool is required to measure the full-field displacement of the complex geometry of the human proximal femur when subjected to axial loads. Optical techniques, such as digital image correlation (DIC), have been used extensively in order to measure planar or volumetric displacement. Even though DIC methods are now in frequent use in experimental bone mechanics, this technique has only recently been reported to measure 3D proximal ex-vivo femur displacement fields during loading under axial loads. The innovation of this study is to extend the use of the DIC technique to visualise and track the progress of failure of the proximal femur under limb stance configuration. An experimental protocol has been proposed and validated on eight human cadaveric femurs. The results indicated that failure takes place by shearing in the head–neck region. Furthermore, it was found that this method enables to extract additional information on the fracture profile and its initiation. The obtained information can facilitate the interpretation of the in vitro failure behaviour of human femur under axial loading conditions which will serve the validation of hip models. © 2015 Taylor & Francis.

Bettamer A.,University of Benghazi | Hambli R.,University of Benghazi | Allaoui S.,Prisme Laboratory | Almhdie-Imjabber A.,Sebha University
Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization | Year: 2017

In this paper, a simple and practical two-dimensional finite element (FE) model coupled to a quasi-brittle damage law has been developed to describe the initiation and progressive propagation of damage of human proximal femur under quasi-static load until complete fracture. In order to validate the model, 10 human proximal femurs were tested till complete fracture under one-legged stance quasi-static load. During each load step, visual image measurements of full-field real-time strain was achieved using a digital image correlation technique consisting in an optical image system with recording cameras linked to a computer with image-processing software. Two-dimensional FE femur models were derived by the projection of micro-computed tomography scans and the specimen fractures were simulated using the same loads and boundary conditions as in the experimental tests. The predicted and optically measured strain field magnitudes and distributions were compared for the 10 specimens. Three femurs were used for calibration of the model and the remaining seven femurs were used for validation. The numerical calibration phase was used to establish the relationship between the FE density and the strain at fracture needed for description of the damage growth. Very good agreement (R2 = 0.89) was obtained between predicted and visualized measured results, indicating that the proposed FE proximal femur fracture model in the quasi-static regime can capture the initiation and propagation of cracks within femurs till complete organ failure. In addition, we show that full-field visual strain measurement provides a much more general and accurate validation than traditional methods based on strain gauges or simple force–displacement curves. The FE model developed here, based on two-dimensional representations of proximal femur geometry and areal bone mineral density distributions, could be applied by clinicians to predict the femur fracture risk of patients using simple and rapid modelling combined with 2D radiographs. © 2015 Taylor & Francis.

Mayyala Q.,King Fahd University of Petroleum and Minerals | Abed-Meraim K.,PRISME Laboratory | Zerguine A.,King Fahd University of Petroleum and Minerals
2017 13th International Wireless Communications and Mobile Computing Conference, IWCMC 2017 | Year: 2017

This paper investigates the impact of certain side information that are available in the channels and/or signals on the blind system identification through the Cramer-Rao Bound (CRB). More precisely, we considered a Single Input Multiple Output (SIMO) system, and studied, for different scenarios, the performance bounds for channel estimation in both deterministic and Bayesian cases. The latter correspond to the situations where side information is brought by either a pilot sequence (semi-blind case), channel sparsity (specular channel case) or certain signal's statistical properties such as the non-circularity. This analysis allows us to have a better understanding of the behavior of the blind channel estimation when the considered side information is taken into account. © 2017 IEEE.

Mayyala Q.,King Fahd University of Petroleum and Minerals | Abed-Meraim K.,PRISME Laboratory | Zerguine A.,King Fahd University of Petroleum and Minerals
IEEE International Conference on Communications | Year: 2017

In this paper, the problem of blind equalization and source separation of convolutive Multi-Input Multi-Output (MIMO) system is solved using Givens/Shear rotations. Targeting the Multi-Modulus (MM) signals and exploiting the second-order decorrelation among the transmitting sources, two efficient Givens Muti-Modulus (G-MMDDA) and Hyperbolic Givens (HG-MMDDA) Deconvolution algorithms are proposed for the first time. These solutions can be seen as extensions of the blind source separation MM-based method by Shah et al (2015) to the more general case of blind deconvolution for memory MIMO channels. The resulting algorithms are quite appealing as they combine both a good speed of convergence with low computational complexity. © 2017 IEEE.

Belayachi N.,PRISME laboratory | Bouasker M.,CNRS Center for Research on Divided Matter | Hoxha D.,PRISME laboratory | Al-Mukhtar M.,CNRS Center for Research on Divided Matter
Applied Mechanics and Materials | Year: 2013

This paper presents an investigation on the use of new light-weight construction material, composed of lime, water and cereal straw fiber. Two types of fibers were used: wheat and barley straw. The influence of some parameters such as fiber types, binder types (lime and/ or limecement), fiber to binder ratio (F/B) and Water to Binder ratio (W/B) on the mechanical and thermal properties is studied. Compressive strength, thermal conductivity and density of the material were investigated. The results indicated that the thermal conductivity of the straw-lime composites decreased with increasing straw content. The result comparisons also revealed that the composite reinforced by wheat straw fibres has the highest compressive strength. © (2013) Trans Tech Publications, Switzerland.

Haritopoulos M.,PRISME Laboratory | Roussel J.,PRISME Laboratory | Capdessus C.,PRISME Laboratory | Nandi A.K.,Brunel University
IFMBE Proceedings | Year: 2014

In this work, a novel method based on the cyclostationary properties of electrocardiogram (ECG) signals is introduced in order to classify independent subspaces into components reflecting the electrical activity of the foetal heart and those corresponding to mother's heartbeats, while the remaining ones are mainly due to noise. This research is inspired from multidimensional independent component analysis (MICA), a method that aims at grouping together into independent multidimensional components blind source separated signals from a set of observations. Given an input set of observations, independent component analysis (ICA) algorithms estimate the latent source signals which are mixed together. In the case of ECG recordings from the maternal thoracic and abdominal areas, the foetal ECGs (FECGs) are contaminated with maternal ECGs (MECG), electronic noise, and various artifacts (respiration, for example). When ICA-based methods are applied to these measurements, many of the output estimated sources have the same physiological origin: the mother's or the foetus' heartbeats. Thereby, we show that a procedure for automatic classification in independent subspaces of the extracted FECG and MECG components is feasible when using a criterion based on the cyclic coherence (CC) of the signal of interest. © Springer International Publishing Switzerland 2014.

Soury H.,King Abdullah University of Science and Technology | Abed-Meraim K.,PRISME Laboratory | Alouini M.-S.,King Abdullah University of Science and Technology
Conference Record - Asilomar Conference on Signals, Systems and Computers | Year: 2015

An impulsive noise environment is considered in this paper. A new aspect of signal truncation is deployed to reduce the harmful effect of the impulsive noise to the signal. A full rank direct solution is derived followed by an iterative solution. The reduced rank adaptive filter is presented in this environment by using two methods for rank reduction, while the minimized objective function is defined using the Lp norm. The results are presented and the efficiency of each method is discussed. © 2014 IEEE.

Mangeot A.,PRISME Laboratory | Mangeot A.,French National Center for Space Studies | Gascoin N.,PRISME Laboratory | Gillard P.,PRISME Laboratory
20th AIAA Computational Fluid Dynamics Conference 2011 | Year: 2011

Hybrid rocket technology is known since the 30's and it is covered by a large number of experimental, fundamental and applied research works. It still suffers from a lack of chemical description and of detailed numerical simulation of core phenomena. Several numerical codes have emerged to simulate hybrid rocket combustion chamber but with limited consideration for detailed chemistry. They generally use global Arrhenius law or tabulated regression rate to simulate the solid fuel pyrolysis and equilibrium calculation for the combustion. A new 2-D transient reactive numerical code is proposed in this paper with the use of detailed chemical mechanisms for both pyrolysis and combustion reactions (over 1000 species and 10000 reactions). The features of the numerical code are presented in this paper, as well as the equations used to model the physical and chemical phenomena. The simplification assumptions are presented and the code validation is proposed through analytical and numerical comparisons with bibliographic data on reference test cases. The heat transfer in solid phase has been validated with a 99, 9% accuracy. The mass and heat transfer in the gas phase have shown a mass and energy conservation of around 99, 7%. The gas flow has been validated also on the boundary layer with more than 99, 5% accuracy. For chemistry phenomena, special treatment must be applied, leading to an error less than 2% on the ignition delay for combustion process. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Boudjelaba K.,Prisme Laboratory | Ros F.,Prisme Laboratory | Chikouche D.,University of mSila | Chikouche D.,Ferhat Abbas University Setif
Expert Systems with Applications | Year: 2014

Although genetic algorithms (GAs) have proved their ability to provide answers to the limitations of more conventional methods, they are comparatively inefficient in terms of the time needed to reach a repeatable solution of desired quality. An inappropriate selection of driving parameters is frequently blamed by practitioners. The use of hybrid schemes is interesting but often limited as they are computationally expensive and versatile. This paper presents a novel hybrid genetic algorithm (HGA) for the design of digital filters. HGA combines a pure genetic process and a dedicated local approach in an innovative and efficient way. The pure genetic process embeds several mechanisms that interact to make the GA self-adaptive in the management of the balance between diversity and elitism during the genetic life. The local approach concerns convergence of the algorithm and is highly optimized so as to be tractable. Only some promising reference chromosomes are submitted to the local procedure through a specific selection process. They are more likely to converge towards different local optima. This selective procedure is fully automatic and avoids excessive computational time costs as only a few chromosomes are concerned. The hybridization and the mechanisms involved afford the GA great flexibility. It therefore avoids laborious manual tuning and improves the usability of GAs for the specific area of FIR filter design. Experiments performed with various types of filters highlight the recurrent contribution of hybridization in improving performance. The experiments also reveal the advantages of our proposal compared to more conventional filter design approaches and some reference GAs in this field of application. © 2014 Elsevier Ltd. All rights reserved.

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