Search results for "artificial intelligence"
showing 10 items of 6122 documents
Darboux curves on surfaces I
2017
International audience; In 1872, G. Darboux defined a family of curves on surfaces of $\mathbb{R}^3$ which are preserved by the action of the Mobius group and share many properties with geodesics. Here, we characterize these curves under the view point of Lorentz geometry and prove that they are geodesics in a 3-dimensional sub-variety of a quadric $\Lambda^4$ contained in the 5-dimensional Lorentz space $\mathbb{R}^5_1$ naturally associated to the surface. We construct a new conformal object: the Darboux plane-field $\mathcal{D}$ and give a condition depending on the conformal principal curvatures of the surface which guarantees its integrability. We show that $\mathcal{D}$ is integrable w…
Automatic detection of P, QRS and T patterns in 12 leads ECG signal based on CWT
2016
International audience; In this paper, a new method based on the continuous wavelet transform is described in order to detect the QRS, P and T waves. QRS, P and T waves may be distinguished from noise, baseline drift or irregular heartbeats. The algorithm, described in this paper, has been evaluated using the Computers in Cardiology (CinC) Challenge 2011 database and also applied on the MIT-BIH Arrhythmia database (MITDB). The data from the CinC Challenge 2011 are standard 12 ECG leads recordings with full diagnostic bandwidth compared to the MITDB which only includes two leads for each ECG signal. Firstly, our algorithm is validated using fifty 12 leads ECG samples from the CinC collection…
A predictive approach for a real-time remote visualization of large meshes
2012
Déjà sur HAL; Remote access to large meshes is the subject of studies since several years. We propose in this paper a contribution to the problem of remote mesh viewing. We work on triangular meshes. After a study of existing methods of remote viewing, we propose a visualization approach based on a client-server architecture, in which almost all operations are performed on the server. Our approach includes three main steps: a first step of partitioning the original mesh, generating several fragments of the original mesh that can be supported by the supposed smaller Transfer Control Protocol (TCP) window size of the network, a second step called pre-simplification of the mesh partitioned, ge…
An original approach for gas chromatography-olfactometry detection frequency analysis: Application to gin
2012
Abstract Gas Chromatography-Olfactometry (GC-O) is a technique that lies halfway between physicochemical and sensory analysis and involves the perception of volatile flavour compounds, separated by gas chromatography, by the human nose. Of the different GC-O procedures available, detection frequency has been proved to be more rapid and more repeatable, even with an untrained panel. This characteristic regarding the panel is often not considered when dealing with the sensory attributes determined by assessors. An original approach to GC-O using the detection frequency procedure has been developed and tested on two types of gin and made it possible to benefit from sensory data. The panel cons…
3D part inspection path planning of a laser scanner with control on the uncertainty
2011
International audience; This article concerns the measurement process of mechanical parts using laser scanners. From the point of view of industrial applications, the objective is to guarantee the measurement accuracy during the scanning with regard to the geometrical product specifications. The proposed method can be summarized as follow: the first step consists of analyzing the interval of tolerance for the different specifications and to attribute to every geometrical entity a maximal uncertainty of measurement. This uncertainty depends on the angle of incidence between the laser plane and the scanned surface. In the second step, an approach based on the concept of visibility is used fro…
3D Displacements and Strains Solid Measurement based on the Surface Texture with a Scanner Laser
2013
International audience; The developments of non-contact measurement are today widely due to the unprecedented progress of optronic. The applications of these techniques are wide and varied for the 3D measurement of industrial products. In addition to the forms and dimensions, we show in this paper that the devices of laser scanning permit to measure displacements and deformations. In this case, it is necessary to follow a solid particle in its motion. It is then necessary to identify the particle between two configurations of the body before and after displacement. The method of greyscale patterns, obtained by applying a spray, is generally used. The originality of the proposed method is ba…
3D digitizing path planning for part inspection with laser scanning
2007
If the first work relating to the automation of the digitalization of machine elements goes back to approximately 25 years, the process of digitalization of parts with non-contact sensor remains nevertheless complex. It is not completely solved today, in particular from a metrological point of view. In this article, we consider the determination of the trajectory planning within the framework of the control of dimensional and geometrical specifications. The sensor used in this application is a laser planner scanner with CCD camera oriented and moved by a CMM. For this purpose, we have focused on the methodology used to determine the best possible viewpoints which will satisfy the digitizing…
Taking digitized points quality into account in geometrical specification measurement by laser sensor
2004
International audience; Today, the new measurement techniques without contact like the laser sensors are used more and more in industrial applications. They allow to obtain many points in a short time. However these techniques have a less good accuracy than the classical process with contact probe for metrology application. The work presented in this paper, is part of a research project on the in-process product inspection. In the case of in-process product inspection, the throughput time must be the shortest with a good dimensional accuracy. So, it is necessary to increase the measurement accuracy of the points cloud for using the laser scanners. For this first approach, we suggest to buil…
Strain fields measurement of non-rigid solid by scanning laser coupled with camera
2013
International audience; Abstract. Today, the techniques of measurement without contact by scanning laser are increasingly used. These techniques allow to measure 3D objects without contact and the measurement rates can reach few thousand points by second that is very adapted to complex shapes. To measure displacements and deformations, it is necessary to follow a solid particle in its motion between two configurations of the body before and after displacement. The method of stereovision based on grayscale patterns, obtained by applying a spray, is generally used. The results are obtained by two correlations: spatial and temporal correlations. An alternative method consists to use a scanner …
Agent-based modelling of urban expansion and land cover change: a prototype for the analysis of commuting patterns in Geneva, Switzerland
2023
Agent-based modelling has been used in many studies of urban expansion, land use and land cover change patterns. While representing a powerful tool for depicting and formulating predictions about the evolution of interconnected complex systems, this method also poses a series of challenges to the researcher community, most notably in terms of model calibration and validation, and output data visualisation. Based on these findings, we present an agent-based model developed in GAMA, coupled with a data exploration platform coded in python, for analysing commuting patterns in the canton of Geneva, Switzerland. Output datasets generated from a set of simple evolution rules for the agents, are d…