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Search Results: 1 - 10 of 4702 matches for " Laurent "
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Marine Biology: A Sub-Sample of a Vast Topic  [PDF]
Laurent Seuront
Open Journal of Marine Science (OJMS) , 2013, DOI: 10.4236/ojms.2013.32A001
Abstract:

Marine Biology: A Sub-Sample of a Vast Topic

Generalized Powers of Substitution with Pre-Function Operators  [PDF]
Laurent Poinsot
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.47A004
Abstract:

An operator on formal power series of the form S \"\" μS , where μ is an invertible power series, and σ is a series of the form t+\"\"(t2) is called a unipotent substitution with pre-function. Such operators, denoted by a pair (μ σ )  , form a group. The objective of this contribution is to show that it is possible to define a generalized powers for such operators, as for instance fractional powers \"\"σ for every\"\" .

The Mediating Role of the Sense of Relatedness and Task Cohesion in the Relation between Psychological Power Distance and Efficicency of a Working Team  [PDF]
Laurent Auzoult
Psychology (PSYCH) , 2013, DOI: 10.4236/psych.2013.410105
Abstract:

Understanding of the effectiveness of work-teams is a major issue in the business world, where they are expected to facilitate developing individual skills and increasing organizations’ efficiency. Eighty-three engineers working in teams have responded to a questionnaire devised to measure perceptual power distances, the sense of relatedness, cohesion measured by integration around the task, and teams’ effectiveness. Results reveal that “task cohesion” and sense of relatedness mediate the relationship between power distance and perceived effectiveness. These results are related with those observed in the context of the self-determination theory and presented in order to highlight their practical implications.

Health 3.0—The patient-clinician “arabic spring” in healthcare  [PDF]
Serge Gagnon, Laurent Chartier
Health (Health) , 2012, DOI: 10.4236/health.2012.42008
Abstract: A growing number of citizen-patients and clinicians use Communication and Self-Managed Health Technologies (CSMHT) in their relationship. Doing so, they shift from the current paradigm of dependency to a co-responsibility paradigm in healthcare. Facing the runaway utilization of health services, we need to think “outside the box” to unblock the system. A Health 3.0 development model of governance that position patients as primary members of the clinicians’ team is presented to map this institutional transformation. At the practical level, an MD 3.0 relational model and a Citizen-Patient 3.0 behavioral profile are presented.
Deploying Safety-Critical Applications on Complex Avionics Hardware Architectures  [PDF]
Robert Hilbrich, Laurent Dieudonné
Journal of Software Engineering and Applications (JSEA) , 2013, DOI: 10.4236/jsea.2013.65028
Abstract:

Aviation electronics (avionics) are sophisticated and distributed systems aboard an airplane. The complexity of these systems is constantly growing as an increasing amount of functionalities is realized in software. Thanks to the performance increase, a hardware unit must no longer be dedicated to a single system function. Multicore processors for example facilitate this trend as they are offering an increased system performance in a small power envelope. In avionics, several system functions could now be integrated on a single hardware unit, if all safety requirements are still satisfied. This approach allows for further optimizations of the system architecture and substantial reductions of the space, weight and power (SWaP) footprint, and thus increases the transportation capacity. However, the complexity found in current safety-critical systems requires an automated software deployment process in order to tap this potential for further SWaP reductions. This article used a realistic flight control system as an example to present a new model-based methodology to automate the software deployment process. This methodology is based on the correctness-by-construction principle and is implemented as part of a systems engineering toolset. Furthermore, metrics and optimization criteria are presented which further help in the automatic assessment and refinement of a generated deployment. A discussion regarding a tighter integration of this approach in the entire avionics systems engineering workflow concludes this article.

Estimating firing rates from calcium signals in locust projection neurons in vivo
Laurent Moreaux,Gilles Laurent
Frontiers in Neural Circuits , 2007, DOI: 10.3389/neuro.04.002.2007
Abstract: Combining intracellular electrophysiology and multi-photon calcium imaging in vivo, we studied the relationship between calcium signals (sampled at 500–750?Hz) and spike output in principal neurons in the locust antennal lobe. Our goal was to determine whether the firing rate of individual neurons can be estimated in vivo with calcium imaging and, if so, to measure directly the accuracy and resolution of our estimates. Using the calcium indicator Oregon Green BAPTA-1, we describe a simple method to reconstruct firing rates from dendritic calcium signals with 80–90% accuracy and 50?ms temporal resolution.
Ordinary Biodiversity, Local Stakeholders and Forest Management as a Driver for Regional Sustainable Development  [PDF]
Hervé Brédif, Laurent Simon
Open Journal of Forestry (OJF) , 2014, DOI: 10.4236/ojf.2014.43032
Abstract:

The protection of biodiversity which had long been bounded up with emblematic “natural” spaces is now increasingly focusing on ordinary biodiversity and rural agricultural land and forests as well as on urban and peri-urban spaces. Such ordinary biodiversity has its own specific features which make it both a relative and uncertain topic of research. Traditional nature protection instruments do not work on this dimension of the planet’s living tissue and new tools need to be deployed in conjunction with regional and local stakeholders that will provide long-term sustainable solutions for biodiversity and for local and regional development more generally. Research conducted on the Plateau de Millevaches explores the possibilities for shared caring for this biodiversity.

Experimental Investigation of Laser Welding Process in Butt-Joint Configurations  [PDF]
Laurent Jacques, Abderrazak El Ouafi
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.51007
Abstract: This paper presents an experimental investigation of laser welding low carbon galvanized steel in butt-joint configurations. The experimental work is focused on the effects of various laser welding parameters on the welds quality. The investigations are based on a structured experimental design using the Taguchi method. Welding experiments are conducted using a 3 kW Nd:YAG laser source. The selected laser welding parameters (laser power, welding speed, laser fiber diameter, gap between sheets and sheet thickness) are combined and used to evaluate the variation of four weld quality attributes (bead width, penetration depth, underfill and hardness) and to identify the possible relationship between welding parameters and weld physical and geometrical attributes. The effects of these parameters are studied using ANOVA to find their contributions to the variation of different weld characteristics. Plots of the main effects and the interaction effects are also used to understand the influence of the welding parameters. The results reveal that all welding parameters are relevant to bead width (BDW) and depth of penetration (DOP) with a relative predominance of laser power and welding speed. The effect of laser fiber diameter on penetration depth is insignificant. Typical gap-dependent weld shapes show that a small gap results in a narrower and deeper weld. Due to the standard sheared edge, an underfill between 5% and 10% occurs for no-gap experiments. The resulting hardness values are relatively similar for all the experimental tests.
Prediction of Weld Joint Shape and Dimensions in Laser Welding Using a 3D Modeling and Experimental Validation  [PDF]
Laurent Jacques, Abderrazak El Ouafi
Materials Sciences and Applications (MSA) , 2017, DOI: 10.4236/msa.2017.811055
Abstract: This paper presents an experimentally validated weld joint shape and dimensions predictive 3D modeling for low carbon galvanized steel in butt-joint configurations. The proposed modelling approach is based on metallurgical transformations using temperature dependent material properties and the enthalpy method. Conduction and keyhole modes welding are investigated using surface and volumetric heat sources, respectively. Transition between the heat sources is carried out according to the power density and interaction time. Simulations are carried out using 3D finite element model on commercial software. The simulation results of the weld shape and dimensions are validated using a structured experimental investigation based on Taguchi method. Experimental validation conducted on a 3 kW Nd: YAG laser source reveals that the modelling approach can provide not only a consistent and accurate prediction of the weld characteristics under variable welding parameters and conditions but also a comprehensive and quantitative analysis of process parameters effects. The results show great concordance between predicted and measured values for the weld joint shape and dimensions.
ANN Based Predictive Modelling of Weld Shape and Dimensions in Laser Welding of Galvanized Steel in Butt Joint Configurations  [PDF]
Laurent Jacques, Abderrazak El Ouafi
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2018, DOI: 10.4236/jmmce.2018.63022
Abstract: The quality assessment and prediction becomes one of the most critical requirements for improving reliability, efficiency and safety of laser welding. Accurate and efficient model to perform non-destructive quality estimation is an essential part of this assessment. This paper presents a structured and comprehensive approach developed to design an effective artificial neural network based model for weld bead geometry prediction and control in laser welding of galvanized steel in butt joint configurations. The proposed approach examines laser welding parameters and conditions known to have an influence on geometric characteristics of the welds and builds a weld quality prediction model step by step. The modelling procedure begins by examining, through structured experimental investigations and exhaustive 3D modelling and simulation efforts, the direct and the interaction effects of laser welding parameters such as laser power, welding speed, fibre diameter and gap, on the weld bead geometry (i.e. depth of penetration and bead width). Using these results and various statistical tools, various neural network based prediction models are developed and evaluated. The results demonstrate that the proposed approach can effectively lead to a consistent model able to accurately and reliably provide an appropriate prediction of weld bead geometry under variable welding conditions.
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