Search results for " Computer science"
showing 10 items of 3983 documents
An empirical study on classical and community-aware centrality measures in complex networks
2021
Community structure is a ubiquitous feature in natural and artificial systems. Identifying key nodes is a fundamental task to speed up or mitigate any diffusive processes in these systems. Centrality measures aim to do so by selecting a small set of critical nodes. Classical centrality measures are agnostic to community structure, while community-aware centrality measures exploit this property. Several works study the relationship between classical centrality measures, but the relationship between classical and community-aware centrality measures is almost unexplored. In this work [1], we answer two questions: (1) How do classical and community-aware centrality measures relate? (2) What is …
A web application for event detection and exploratory data analysis for Twitter data
2015
International audience
Localization from inertial data and sporadic position measurements
2020
International audience; A novel estimation strategy for inertial navigation in indoor/outdoor environments is proposed with a specific attention to the sporadic nature of the non-periodic measurements. After introducing the inertial navigation model, we introduce an observer providing an asymptotic estimate of the plant state. We use a hybrid dynamical systems representation for our results, in order to provide an effective, and elegant theoretical framework. The estimation error dynamics with the proposed observer shows a peculiar cascaded interconnection of three subsystems (allowing for intuitive gain tuning), with perturbations occurring either on the jump or on the flow dynamics (depen…
Performance evaluation of Wireless Sensor Networks based on ZigBee technology in smart home
2013
International audience; Wireless Sensor Networks (WSNs) has diverse application domains such as smart home, smart care, industrial, etc. In this paper, we present a WSN system based on the ZigBee technology (IEEE 802.15.4) in Smart Home. To have a good sensor networks communication implanted in a smart home, studies of operating performance on this network is important. In this work, we investigate the performance of our ZigBee sensor networks. The study of performance is based on measurements of the Received Signal Strength Indicator (RSSI) in different parts of the Home. We will also discuss the impact of electromagnetic noise on the communication performance of a ZigBee Sensor Network in…
Stratified Autocalibration of Cameras with Euclidean Image Plane
2020
International audience; This paper tackles the problem of stratified autocalibration of a moving camera with Euclidean image plane (i.e. zero skew and unit aspect ratio) and constant intrinsic parameters. We show that with these assumptions, in addition to the polynomial derived from the so-called modulus constraint, each image pair provides a new quartic polynomial in the unknown plane at infinity. For three or more images, the plane at infinity estimation is stated as a constrained polynomial optimization problem that can efficiently be solved using Lasserre's hierarchy of semidefinite relaxations. The calibration parameters and thus a metric reconstruction are subsequently obtained by so…
Implémentation en temps réel d'une architecture embarquée pour le comptage de passagers dans le transport public
2018
Automatisation de l'évaluation de la Fraîcheur des produits de la mer par imagerie couleur
2002
Real-time implementation of counting people in a crowd on the embedded reconfigurable architecture on the unmanned aerial vehicle
2020
The crowd counting task is an important research problem. Now more and more people are concerned about safety issues. Considering the scenario of a crowded scene: a population density system analyzes the crowds and triggers a warning to divert the crowds when their population density exceeds a normal range. With such a system, the incident of the Shanghai New Year's stampede will not happen again. The most difficult problem of population counting at present: On the one hand, in the densely populated area, how to make the model distinguish human head features more finely, such as head overlap. The second aspect is to find a small-scale local head feature in an image with a wide range of popu…
Non conventional Imaging Systems for 3D Digitization of transparent and/or specular manufactured objects
2013
International audience; 3D scanning has been investigated for several years and most of the proposed approaches assume a diffuse or near diffuse reflectance of the object's surface, also called cooperative surfaces. For the case of "non cooperative surfaces", such as transparent objects or mirror-like surfaces, usually, a thin layer of powder is sprayed onto the object surface (to make it opaque and diffuse) prior to its digitization. This extra step is troublesome, time consuming (the object needs to be cleaned afterwards), and the final accuracy is often dependent on the powder thickness and its homogeneousness. To avoid this step, various methods have been investigated over the last few …
A reference free approach for the comparative evaluation of eight segmentation methods for the estimation of the left ventricular ejection fraction i…
2012
International audience; Objective evaluation and comparison of segmentation algorithms for medical imaging is still a challenging issue. The most frequently used evaluation method consists in comparing the segmentation with a manual delineation. Since obtaining such manual segmentation can be tedious, we proposed a method based on the "extended Regression Without Truth" approach (eRWT)(1). This approach is applied to the comparative evaluation of 8 segmentation algorithms with different degrees of automation from the estimated left ventricular ejection fraction (LVEF).