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A robust multi-objective and multi-physics optimization of multi-physics behavior of microstructure

Journal of Central South University 2016年第12期23卷 3225-3238页

作者： Hamda Chagraoui Mohamed Soula Mohamed Guedri Research Unit in Structural Dynamics Modeling and Engineering of Multi-Physics SystemsSDMESMNabeul Preparatory Engineering Institute-IPEINUniversity of Carthage Laboratory of Applied Mechanics and Engineering ENITDepartment of Mechanical engineering ENSITTunis University of Tunisia

A new strategy is presented to solve robust multi-physics multi-objective optimization problem known as improved multi-objective collaborative optimization （IMOCO） and its extension improved multi-objective robust collaborative （IMORCO）. In this work, the proposed IMORCO approach combined the IMOCO method, the worst possible point （WPP） constraint cuts and the Genetic algorithm NSGA-II type as an optimizer in order to solve the robust optimization problem of multi-physics of microstructures with uncertainties. The optimization problem is hierarchically decomposed into two levels： a microstructure level, and a disciplines levels, For validation purposes, two examples were selected： a numerical example, and an engineering example of capacitive micro machined ultrasonic transducers （CMUT） type. The obtained results are compared with those obtained from robust non-distributed and distributed optimization approach, non-distributed multi-objective robust optimization （NDMORO） and multi-objective collaborative robust optimization （McRO）, respectively. Results obtained from the application of the IMOCO approach to an optimization problem of a CMUT cell have reduced the CPU time by 44% ensuring a Pareto front close to the reference non-distributed multi-objective optimization （NDMO） approach （mahalanobis distance, D2M =0.9503 and overall spread, So=0.2309）. In addition, the consideration of robustness in IMORCO approach applied to a CMUT cell of optimization problem under interval uncertainty has reduced the CPU time by 23% keeping a robust Pareto front overlaps with that obtained by the robust NDMORO approach （D2M =10.3869 and So=0.0537）.

关键词： multi-physics multi-objective optimization robust optimization collaborative optimization non-distributed anddistributed optimization uncertainty interval

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Implementation of a Biometric Interface in Voice Controlled Wheelchairs

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Sound & Vibration 2020年第1期54卷 1-15页

作者： Lamia Bouafif Noureddine Ellouze National Institute of Biomedical Studies of Tunis 1092TunisTunisia Image and Signal Processing Laboratory ENIT BP 37University of Tunis El Manar1064Tunisia

In order to assist physically handicapped persons in their movements,we developed an embedded isolated word speech recognition system(ASR)applied to voice control of smart ***,in spite of the existence in the industrial market of several kinds of electric wheelchairs,the problem remains the need to manually control this device by hand via joystick;which limits their use especially by people with severe ***,a significant number of disabled people cannot use a standard electric wheelchair or drive it with *** proposed solution is to use the voice to control and drive the wheelchair instead of classical *** intelligent chair is equipped with an obstacle detection system consisting of ultrasonic sensors,a moving navigation algorithm and a speech acquisition and recognition module for voice control embedded in a DSP *** ASR architecture consists of two main *** first one is the speech parameterization module(features extraction)and the second module is the classifier which identifies the speech and generates the control word to motors power *** training and recognition phases are based on Hidden Markov Models(HMM),K-means,Baum-Welch and Viterbi *** database consists of 39 isolated speaker words(13 words pronounced 3 times under different environments and conditions).The simulations are tested under Matlab environment and the real-time implementation is performed by C language with code composer studio embedded in a TMS 320 C6416 DSP *** results and experiments obtained gave promising recognition ratio and accuracy around 99%in clean ***,the system accuracy decreases considerably in noisy environments,especially for SNR values below 5 dB(in street:78%,in factory:52%).

关键词： Handicapped persons smart wheelchairs voice control speech recognition training and classification

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The effects of the rotor-stator interaction on unsteady pressure pulsation and radial force in a centrifugal pump

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Journal of Hydrodynamics 2018年第4期30卷 672-681页

作者： Issa Chalghoum Sami Elaoud Hatem Kanfoudi Mohsen Akrout Research Laboratory "Applied Fluid Mechanics Process and Environment Engineering" National Engineering School of Sfax Sfax Tunisia Research Laboratory "Laboratory of Hydraulics and Environment Modeling" National Engineering School of Tunis ENIT Hydraulic Engineering Tunis Tunisia

An unsteady numerical analysis has been conducted to study the strong interaction between impeller blade and volute tongue of a centrifugal pump. The 3-D-URANS equations were solved with the shear stress transport turbulence model for a wide range of flow rates. These unsteady interactions are mostly related to the unsteady radial force due to an imbalance in the pressure field at the impeller periphery. This force represents dynamic load that are one of the most important sources of vibration and hydraulic noise. Based on this phenomenon, this work analyzes and gives a more realistic prediction of the pressure fluctuation and the radial force during steady and unsteady calculation by considering the effect of the change in the pump operating point. Actually, the pressure fluctuations in the impeller and the volute were recorded by mounting nine monitoring points on the impeller and volute casing. The results of the existing analysis has proven that the pressure fluctuation is periodic due to the relative position of impeller blade to volute tongue. The characteristics of the time domain and frequency domain of the pressure pulsation were analyzed under different coupling conditions. Fast Fourier transform was performed to obtain the spectra of pressure pulsation. Besides, the steady and unsteady forces were calculated around the impeller periphery to fully characterize the pump behavior. The obtained pump performance curves were numerically compared with the experimental ones, and the outcome have shown an acceptable agreement between both curves.

关键词： Unsteady simulation blade-tongue interaction unsteady pressure distribution blade-passing frequency

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An ethically guided preclinical device for phenotyping H_(2)production in laboratory rodents

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Animal Models and Experimental Medicine 2024年第4期7卷 553-561页

作者： Victor Pascal-Moussellard Emilie Boucher Stéphane Tanguy Philippe Cinquin Pierre-Alain Barraud ChloéDavin Cordélia Salomez-Ihl Dalil Hannani François Boucher Jean-Pierre Alcaraz University Grenoble Alpes CNRSUMR 5525VetAgro SupGrenoble INPTIMCGrenobleFrance

Background:Dihydrogen(H_(2))is produced endogenously by the intestinal microbiota through the fermentation of diet *** the past few years,numer-ous studies have demonstrated the significant therapeutic potential of H_(2)in various pathophysiological contexts,making the characterization of its production in labora-tory species of major preclinical ***:This study proposes an innovative solution to accurately monitor H_(2)pro-duction in free-moving rodents while respecting animal welfare *** devel-oped device consisted of a wire rodent cage placed inside an airtight chamber in which the air quality was maintained,and the H_(2)concentration was continuously *** the airtightness and efficiency of the systems used to control and maintain air quality in the chamber were checked,tests were carried out on rats and mice with different metabolic phenotypes,over 12 min to 1-h experiments and repeatedly.H_(2)production rates(HPR)were obtained using an easy calculation algorithm based on a first-order moving ***:HPR in hyperphagic Zucker rats was found to be twice as high as in control Wistar rats,respectively,2.64 and 1.27 nmol.s^(−1)per *** addition,the ingestion of inulin,a dietary fiber,stimulated H_(2)production in *** were 0.46 nmol.s^(−1)for animals under control diet and 1.99 nmol.s^(−1)for animals under inulin ***:The proposed device coupled with our algorithm enables fine analysis of the metabolic phenotype of laboratory rats or mice with regard to their endogenous H_(2)production.

关键词： hydrogen therapy laboratory rodents microbiota molecular hydrogen noninvasive monitoring device

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Immunobiodiversity:Conserved and specific immunity across land plants and beyond

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Molecular Plant 2024年第1期17卷 92-111页

作者： Baptiste Castel Karima El Mahboubi Christophe Jacquet Pierre-Marc Delaux Laboratoire de Recherche en Sciences Végétales(LRSV) Universitéde ToulouseCNRSUPSToulouse INPCastanet-TolosanFrance

Angiosperms represent most plants that humans cultivate,grow,and ***,angiosperms are only one of five major land plant *** a whole lineage,plants also include algal *** these clades represent a tremendous genetic diversity that can be investigated to reveal the evolutionary history of any given *** this review,we describe the current model of the plant immune system,discuss its evolution based on the recent literature,and propose future directions for the *** angiosperms,plant–microbe interactions have been intensively studied,revealing essential cell surface and intracellular immune receptors,as well as metabolic and hormonal defense *** diversity at the genomic and functional levels demonstrates the conservation of these pathways across land plants,some of which are beyond *** basis of the conserved mechanisms,lineage-specific variations have occurred,leading to diversified reservoirs of immune *** rare cases,this diversity has been harnessed and successfully transferred to other species by integration of wild immune receptors or engineering of novel forms of receptors for improved resistance to *** propose that exploring further the diversity of immune mechanisms in the whole plant lineage will reveal completely novel sources of resistance to be deployed in crops.

关键词： evolution MPMI immunity plant evoMPMI symbiosis

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Acquired cancer tyrosine kinase inhibitor resistance: ROS as critical determinants

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Signal Transduction and Targeted Therapy 2022年第1期7卷 17-18页

作者： Sander Bekeschus ZIK plasmatis Leibniz Institute for Plasma Science and Technology(INP)Felix-Hausdorff-Str.217489 GreifswaldGermany

The ability of a minority of cancer cells lineages to withstand drug-induced toxicity and re-enter cell cycling in the presence of the drug has been observed for long,but the underlying mechanisms remained *** work published in Nature by Oren and colleagues used barcode lentiviral library labeling to prominently discern antioxidant profiles,among others,being the primary underlying cellular program that governs proliferation under tyrosine kinase inhibitor(TKI)drug pressure.^(1)

关键词： cancer drug cycling

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Edge Computing Based Applications in Vehicular Environments:Comparative Study and Main Issues

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Journal of Computer Science & Technology 2019年第4期34卷 869-886页

作者： Leo Mendiboure Mohamed-Aymen Chalouf Francine Krief LaBRI Laboratory University of BordeauxTalence 33400France IRISA Laboratory University of Rennes 1Lannion 22300France LaBRI Laboratory Bordeaux INPTalence 33400France

Despite the expanded efforts,the vehicular ad-hoc networks(VANETs)are still facing many challenges such as network performances,network scalability and *** solutions have been proposed to overcome these obstacles,and the edge computing,an extension of the cloud computing,is one of *** edge computing,communication,storage and computational capabilities are brought closer to end *** could offer many benefits to the global vehicular network including,for example,lower latency,network off-loading and context-awareness(location,environment factors,etc.).Different approaches of edge computing have been developed:mobile edge computing(MEC),fog computing(FC)and cloudlet are the main *** introducing the vehicular environment background,this paper aims to study and compare these different *** that purpose their main features are compared and the state-of-the-art applications in VANETs are *** addition,MEC,FC,and cloudlet are classified and their suitability level is debated for different types of vehicular ***,some challenges and future research directions in the fields of edge computing and VANETs are discussed.

关键词： cloud computing edge computing fog computing cloudlet vehicular network

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How can inter-specific interferences explain coexistence or confirm the competitive exclusion principle in a chemos tat?

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International Journal of Biomathematics 2018年第8期11卷 307-326页

作者： Mi led El Hajji enit-LAMSIN BP. 37 1002 Tunis-Belvedere Tunis El Manar University Tunis Tunisia General Studies Department College of Telecom and Electronics Technical and Vocational Training Corporation Jeddah 2146 Saudi Arabia

In this paper, I consider two species feeding on limiting substrate in a chemostat taking into account some possible effects of each species on the other one. System of differential equations is proposed as model of these effects with general inter-specific density-dependent growth rates. Three cases were considered. The first one for a mutual inhibitory relationship where it is proved that at most one species can survive which confirms the competitive exclusion principle. Initial concentrations of species have great importance in determination of which species is the winner. The second one for a food web relationship where it is proved that under general assumptions on the dilution rate, both species persist for any initial conditions. Finally, a third case dealing with an obligate mutualistic relationship was discussed. It is proved that initial condition has a great importance in determination of persistence or extinction of both species.

关键词： Chemostat mutual-inhibition food web obligate mutualism asymptotic behavior coexistence competitive exclusion principle dulac criterion thieme's result

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A Generalized Non-Linear Flow Law Based on Modified Zerilli-Armstrong Model and Its Implementation into Abaqus/Explicit FEM Code

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World Journal of Engineering and Technology 2022年第2期10卷 334-362页

作者： Pierre Tize Mha Amèvi Tongne Olivier Pantalé Production Engineering Laboratory INPT/ENIT Toulouse University Tarbes France

Non-linear numerical modeling, widely used in research and development to understand many complex processes such as forming or machining, does not guarantee the success of a study to be performed. Indeed, the numerical simulation uses finite element codes where the models already integrated are not based on shapes adjustable to any type of study. In this study, a new form of non-linear constitutive flow law based on the Modified Zerilli-Armstrong model, which can answer the above problem, has been developed to apply it to the numerical simulation of two different tests (a quasi-static compression test, the necking of a circular bar). This flow law is based on the modified Zerilli-Armstrong model, which, together with the new modified Johnson-Cook model, has been compared to appreciate the relevance of the proposal. For that, an implementation of this new law via the VUHARD subroutine into the Abaqus/Explicit finite element code was made to model the two tests. The comparison of the results obtained (from identification) by our proposed law with those obtained using the NMJC shows that this new law better approaches the experiments than the other one. This is also shown through the numerical results using the Abaqus software. It can be said that this way of formulating a flow law allows highlighting the great performance of the proposed approach. Although this law has been only used for quasi-static tests, we can say that it can also be used in dynamic tests.

关键词： Zerilli-Armstrong Flow Law Constitutive Behavior Finite Element Method Numerical Implementation Johnson-Cook Flow Law

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Preparation and Properties of Cellulose Nanomaterials

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Paper And Biomaterials 2020年第3期5卷 1-13页

作者： Alain Dufresne UniversitéGrenoble Alpes CNRSGrenoble INPLGP2GrenobleF-38000France

Cellulose is the most abundant biomass material in nature and it is mainly extracted from natural or lignocellulosic *** purification,cellulose fibers exhibit two interesting features for their further transformation into nanomaterials:a hierarchical and multi-level strcture,and a semicrystalline *** forms of cellulose nanomaterials,resulting from a top-down deconstructing strategy(cellulose nanocrystals(CNCs),cellulose nanofibrils(CNFs))or bottom-up strategy(bacterial cellulose(BC))can be *** mechanical shearing actions applied to cellulosic fibers release more or less the nanofibrils individually.A controlled strong acid hydrolysis treatment can be applied to cellulosic fibers allowing dissolution of non-crystalline *** cellulose nanomaterials have been the focus of an exponentially increasing number of works or reviews devoted to understand such materials and their *** have a high potential for an emerging *** the nanoscale,cellulose exhibits specific properties broadening the applications of this naturally occurring *** overview of existing methods for the preparation of cellulose nanomaterials and their specific properties that outperform and contrast with cellulose in the microscale is proposed.

关键词： cellulose nanomaterial nanocrystal nanofibril preparation properties

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