104 research outputs found
Assignation dynamique de positions pour les déplacements en formation d'un groupe de robots
Permettre Ă un groupe de robots de se dĂ©placer dans une configuration particuliĂšre est une fonctionnalitĂ© intĂ©ressante pour lâexploration, la cartographie et la recherche sur de grandes surfaces. Cependant, il est injustifiĂ© de supposer que tous les robots puissent rester positionnĂ©s correctement lors de tels dĂ©ploiements. Pour y arriver, une approche permettant Ă un groupe de robots mobiles de dĂ©terminer de maniĂšre autonome lâassignation de leur position dans une formation demandĂ©e, et ce, dâaprĂšs la disposition initiale du groupe et de la formation voulue, est proposĂ©e. Lâapproche DRF (Dynamic Robot Formations) rĂ©alisĂ©e est distribuĂ©e et fonctionne avec un nombre variable de robots. Percevant les autres dans leur entourage par leur systĂšme de vision, les robots communiquent entre eux les positions perçues afin que chacun puisse avoir une idĂ©e de la disposition du groupe. Chaque robot utilise alors ces informations afin de dĂ©terminer quelle serait la meilleure assignation de position en se considĂ©rant lui-mĂȘme comme le conducteur du groupe. Cette recherche dâassignation est effectuĂ©e de façon disÂtribuĂ©e Ă lâaide dâun algorithme de recherche profondeur dâabord bornĂ© avec coupure (pruning), cherchant Ă minimiser les dĂ©placements des robots du groupe pour rĂ©aliser la formation. Le robot ayant le meilleur rĂ©sultat est sĂ©lectionnĂ© comme le conducteur de la formation, et assigne la position des autres robots du groupe. La validation du systĂšme sâeffectue Ă lâaide dâun environnement simulĂ© de robots mobiles, ainsi quâavec de vraies plates-formes robotiques. Les rĂ©sultats obtenus dĂ©montrent que lâapproche DRF est flexible et valable pour une multitude de situations et dâenvironnements, en plus dâillustrer que le mĂ©canisme dâassiÂgnation de positions dans la formation minimise lâensemble des dĂ©placements du groupe de robots
Ălaboration d'un intergiciel pour relier les instruments aux grids
Les logiciels Grid sont en train de devenir une partie intĂ©grale de la science Ă©lectronique puisque la science moderne a besoin d'une grande capacitĂ© de calcul et une grande base de donnĂ©es d'information. Afin d'avoir des logiciels Grid capables de s'intĂ©grer avec la science d'aujourd'hui, il faut que les instruments de mesure soient accessibles et reprĂ©sentĂ©s grĂące Ă des intergiciels Grid de façon Ă ce qu'ils fassent partie de la Grid. Ce mĂ©moire prĂ©sente un rĂ©sumĂ© de la technologie des Grids, la conception du modĂšle et l'implĂ©mentation initiale de l'intergiciel appelĂ© Grid Resource Instrument Model (GRIM) bĂąti Ă l'aide du WSRF pour les instruments et capteurs et inspirĂ© par les standards IEEE1451, SensorML et TML. Le rĂ©sultat de cette recherche est un intergiciel qui peut ĂȘtre utilisĂ© par des applications Grid Ă des fins telles la planification et partage de laboratoires, le contrĂŽle Ă distance d'instruments et la surveillance de capteurs
PrivaTree: Collaborative Privacy-Preserving Training of Decision Trees on Biomedical Data
Biomedical data generation and collection have become faster and more ubiquitous. Consequently, datasets are increasingly spread across hospitals, research institutions, or other entities. Exploiting such distributed datasets simultaneously can be beneficial; in particular, classification using machine learning models such as decision trees is becoming increasingly common and important. However, given that biomedical data is highly sensitive, sharing data records across entities or centralizing them in one location are often prohibited due to privacy concerns or regulations. We design PrivaTree, an efficient and privacy-preserving protocol for collaborative training of decision tree models on distributed, horizontally partitioned, biomedical datasets. Although decision tree models may not always be as accurate as neural networks, they have better interpretability and are helpful in decision-making processes, which are crucial for biomedical applications. PrivaTree follows a federated learning approach, where raw data is not shared, and where every data provider computes updates to a global decision tree model being trained, on their private dataset. This is followed by privacy-preserving aggregation of these updates using additive secret-sharing, in order to collaboratively update the model. We implement PrivaTree, and evaluate its computational and communication efficiency on three different biomedical datasets, as well as the accuracy of the resulting models. Compared to the model centrally trained on all data records, the obtained collaborative model presents a modest loss of accuracy, while consistently outperforming the accuracy of the local models, trained separately by each data provider. Moreover, PrivaTree is more efficient than existing solutions, which makes it usable for training decision trees with numerous nodes, on large complex datasets, with both continuous and categorical attributes, as often found in the biomedical field
Secure Stream Processing for Medical Data
Medical data belongs to whom it produces it. In an increasing manner, this
data is usually processed in unauthorized third-party clouds that should never
have the opportunity to access it. Moreover, recent data protection regulations
(e.g., GDPR) pave the way towards the development of privacy-preserving
processing techniques. In this paper, we present a proof of concept of a
streaming IoT architecture that securely processes cardiac data in the cloud
combining trusted hardware and Spark. The additional security guarantees come
with no changes to the application's code in the server. We tested the system
with a database containing ECGs from wearable devices comprised of 8 healthy
males performing a standarized range of in-lab physisical activities (e.g.,
run, walk, bike). We show that, when compared with standard Spark Streaming,
the addition of privacy comes at the cost of doubling the execution time
Reovirus Ό2 protein modulates host cell alternative splicing by reducing protein levels of U5 snRNP core components
Abstract : Mammalian orthoreovirus (MRV) is a doublestranded RNA virus from the Reoviridae family presenting a promising activity as an oncolytic virus. Recent studies have underlined MRVâs ability to alter cellular alternative splicing (AS) during infection, with a limited understanding of the mechanisms at play. In this study, we investigated how MRV modulates AS. Using a combination of cell biology and reverse genetics experiments, we demonstrated that theM1 gene segment, encoding the ÎŒ2 protein, is the primary determinant of MRVâs ability to alter AS, and that the amino acid at position 208 in ÎŒ2 is critical to induce these changes. Moreover, we showed that the expression of ÎŒ2 by itself is sufficient to trigger AS changes, and its ability to enter the nucleus is not required for all these changes. Moreover, we identified core components of the U5 snRNP (i.e. EFTUD2, PRPF8, and SNRNP200) as interactors of ÎŒ2 that are required for MRV modulation of AS. Finally, these U5 snRNP components are reduced at the protein level by both MRV infection and ÎŒ2 expression. Our findings identify the reduction of U5 snRNP components levels as a new mechanism by which viruses alter cellular AS
Non-invasive pulmonary artery pressure estimation by electrical impedance tomography in a controlled hypoxemia study in healthy subjects.
Pulmonary hypertension is a hemodynamic disorder defined by an abnormal elevation of pulmonary artery pressure (PAP). Current options for measuring PAP are limited in clinical practice. The aim of this study was to evaluate if electrical impedance tomography (EIT), a radiation-free and non-invasive monitoring technique, can be used for the continuous, unsupervised and safe monitoring of PAP. In 30 healthy volunteers we induced gradual increases in systolic PAP (SPAP) by exposure to normobaric hypoxemia. At various stages of the protocol, the SPAP of the subjects was estimated by transthoracic echocardiography. In parallel, in the pulmonary vasculature, pulse wave velocity was estimated by EIT and calibrated to pressure units. Within-cohort agreement between both methods on SPAP estimation was assessed through Bland-Altman analysis and at subject level, with Pearson's correlation coefficient. There was good agreement between the two methods (inter-method difference not significant (Pâ>â0.05), biasâ±âstandard deviation ofâ-â0.1â±â4.5 mmHg) independently of the degree of PAP, from baseline oxygen saturation levels to profound hypoxemia. At subject level, the median per-subject agreement was 0.7â±â3.8 mmHg and Pearson's correlation coefficient 0.87 (Pâ<â0.05). Our results demonstrate the feasibility of accurately assessing changes in SPAP by EIT in healthy volunteers. If confirmed in a patient population, the non-invasive and unsupervised day-to-day monitoring of SPAP could facilitate the clinical management of patients with pulmonary hypertension
FDG-PET/CT for pre-operative staging and prognostic stratification of patients with high-grade prostate cancer at biopsy
Actes du 12e Colloque annuel des étudiant-e-s de cycles supérieurs du CRISES
La 12e Ă©dition du Colloque annuel des Ă©tudiant-e-s de cycles supĂ©rieurs du CRISES sâest tenue les 25 et 26 mars 2010 Ă lâUniversitĂ© Laval.
Trente et une (31) communications y ont Ă©tĂ© prĂ©sentĂ©es sur des thĂšmes aussi diversifiĂ©s que le Vieillissement au travail, les Grappes industrielles, lâImmigration, les DĂ©fis de la gouvernance, la Gestion des ressources et les solidaritĂ©s locales, incluant un atelier spĂ©cial sur les AvancĂ©es et les limites de lâinnovation sociale.
Les textes qui nous sont parvenus avant la date limite du 18 mars afin dâĂȘtre soumis Ă un processus dâĂ©valuation, ainsi que respectivement le texte et/ou les diapositives PowerPoint des confĂ©renciers dâouverture et de clĂŽture sont contenus dans ces Actes.
Nous tenons ici à remercier chaleureusement nos collÚgues du comité organisateur : Kamel Béji, Manon Boulianne et Frédéric Hanin et notre assistante : Carole-Anne Gauthier."VIEILLISSEMENT AU TRAVAIL"
"APPROCHES DE LA GOUVERNANCE"
"GRAPPES INDUSTRIELLES ET DĂVELOPPEMENT LOCAL"
"GESTION DES RESSOURCES"
"SOLIDARITĂS LOCALES"
"IMMIGRATION ET IDENTITĂ"
"L'INNOVATION SOCIALE: AVANCĂES ET LIMITES
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