Search results for " Computer Science"
showing 10 items of 3983 documents
Semantics for Spatio-temporal "Smart Queries"
2013
International audience; There is a demand to enhance the meaning of objects and their relationships in the geospatial domain.This need has led to a new fi eld of research called geosemantics, which takes advantage of state of art databases and inference mechanism of ontologies. Current geosemantic proposals involve mixed solutions using spatial databases to store geographic objects and a separate ontology to provide semantic capabilities to the system. However making a simple query involves requesting information from both components which is problematic. In our previous work we proposed a functional standalone based architecture, that uses SWRL to solve spatio-temporal problems.In this pap…
LC3 A Spatial-temporal Data Model to Study Qualified Land Cover Changes
2015
International audience; Land cover changes caused by humans have reached points never witnessed in history before. Consequences of these changes are environmental degradation, pollution of water, biodiversity loss and climate change among others. It is in this frame that the interest of the scientific community for this type of events has increased in the last decades. Nowadays, researchers have access to sophisticated monitoring tools and techniques. However, the new threat is that over abundance of information would hide relevant facts and processes. In our research we use data from the CORINE (Coordination of Information on the Environment) program. This program has compiled land cover i…
Using Semantic Web Technologies to Follow the Evolution of Entities in Time and Space
2013
International audience; In this paper we present the "continuum model". Our work follows a "perdurantism" approach and is designed to handle dynamic phenomena extending the 4D-fluent with the use of semantic web technologies. In our approach we represent dynamic entities as constituted by timeslices each with semantic, geometric, temporal and identity components. Our model is able to link the diverse representations of an entity and allows the inference of qualitative information from quantitative one. The inference results are later added to the ontology in order to improve knowledge about the phenomenon. The model has been implemented using OWL and SWRL. Our preliminary results are promis…
Interaction peripheral device capable of controlling an element for touching and grasping multidimensional virtual objects
2015
An interaction peripheral device capable of controlling an element for touching and grasping multidimensional virtual objects, including at least two interaction modules, each interaction module being intended to be actuated by a finger of an operator and including a control sensor allowing control of displacement, according to a predetermined number of degrees of freedom, of a portion of the element for touching and grasping virtual objects by bending/extending and/or adduction/abduction displacement of the finger of the operator, and a vibrator able to emit a vibration upon touching and/or letting go of a virtual object by a portion of said element for touching and grasping virtual object…
Automatic classification of tissues using T1 and T2 relaxation times from prostate MRI: a step toward generation of PET/MR attenuation map
2015
This paper presents a new methodology providing the first step towards generating attenuation maps for PET/MR systems based solely on MR information. The new method segments and classifies the attenuation-differing regions of the patient's pelvis based on acquired T 1 - and T 2 -weighted MR data sets and anatomical-based knowledge by computing the tissue specific T 1 and T 2 relaxation times, using a robust implementation of the weighted fuzzy C-means algorithm and applying a novel process to detect bones. We have demonstrated the feasibility of this approach by correctly segmenting and classifying six differing regions of structural and anatomical importance: fat, muscle, prostate, air, ba…
Cardiac motion tracking using a deformable 2D-mesh modeling
2001
International audience; Abstract: The work reported here deals with movement tracking in sequences of medical images in order to quantify the general movements and deformations of the heart For this purpose, we partition the first image into triangular patches in order that each object of the image corresponds to a set of triangles. Then, the nodes of the mesh are tracked across the image sequence giving a mesh which warps with the images. The method is applied to cardiac image sequences where the study of the deformation of the triangles is applied to the determination of the movement of the ventricles
NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY OF EXCISED HUMAN HEARTS
1992
International audience; Abstract: Background-Phosphorus nuclear magnetic resonance spectroscopy has been proposed as a method of studying the metabolism of the myocardium in patients. Little is known about P-31 nuclear magnetic resonance spectroscopy of diseased human hearts. Methods-Two donor hearts meeting the requirements for heart transplantation and 11 diseased hearts were removed during a transplantation procedure and were studied in a horizontal 2-35 T superconducting magnet. Spectra were obtained at 0-degrees-C about 30 minutes after the excision. The areas of the inorganic phosphate peak (Pi) and of the phosphocreatine peak (PCr) were summed and expressed as a ratio with respect to…
A Mumford-Shah functional based variational model with contour, shape, and probability prior information for prostate segmentation
2012
Abstract: Inter patient shape, size and intensity variations of the prostate in transrectal ultrasound (TRUS) images challenge automatic segmentation of the prostate. In this paper we propose a variational model driven by Mumford-Shah (MS) functional for segmenting the prostate. Parametric representation of the implicit curve is derived from principal component analysis (PCA) of the signed distance representation of the labeled training data to impose shape prior. Posterior probability of the prostate region determined from random forest classification facilitates initialization and propagation of our model in a MS energy minimization framework. The proposed method achieves mean Dice simila…
PROSTATEANALYZER: GUI ALLOWING THE MANAGEMENT OF EXAMINATIONS OF PROSTATE CANCER
2012
International audience; We propose a framework that comprises visualization and analysis for MR imaging of the prostate and a new storage system of clinical diagnoses in a single package. ProstateAnalyzer is such a network-based database system allowing the management of both MRI and spectroscopy data sets, and performing some basic mathematical operations to analyze a set of prostate images.
L'imagerie par résonance magnétique du myocarde avec des agents de contraste extracellulaires à base de gadolinium.
2001
L'injection en bolus d'un agent de contraste extra-cellulaire contenant du gadolinium permet d'étudier le premier passage myocardique et le rehaussement tardif du myocarde chez les patients atteints de maladie coronarienne. Les applications les plus développées concernent l'évaluation de la viabilité. Celle-ci est réduite lorsque l'apparition du signal myocardique au premier passage est lente avec un rehaussement tardif transmural du signal myocardique. À partir des courbes de premier passage, il est possible d'étudier la perfusion myocardique et les effets des agents vasodilatateurs comme le dipyridamole ou l'adénosine. Le débit myocardique absolu peut aussi être calculé. Néanmoins, l'usag…