François Chung, Ph.D.

Tag: real-time

CBM 2009 - Conference

CBM 2009 – Conference proceeding

|

Publication

Tobias Heimann, François Chung, Hans Lamecker, Hervé Delingette; Subject-specific ligament models: Towards real-time simulation of the knee joint; CBM 2009: Computational Biomechanics for Medicine IV, London, 2009.

Abstract

We present an efficient finite element method to simulate a transversely isotropic non-linear material for ligaments. The approach relies on tetrahedral elements and exploits the geometry to optimize computation of the derivatives of the strain energy. To better support incompressibilty, deviatoric and dilational responses are uncoupled and a penalty term controls volume preservation. We derive stress and elasticity tensors required for implicit solvers and verify our model against the FEBio software using a variety of load scenarios with synthetic shapes. The maximum node positioning error for ligament materials is < 5% for strains under physiological conditions. To generate subject-specific ligament models, we propose a novel technique to estimate fiber orientation from segmented ligament geometry. The approach is based on an automatic centerline extraction and generation of the corresponding diffusion field. We present results for a medial collateral ligament segmented from standard Magnetic Resonance Imaging (MRI) data. Results show the general viability of the method, but also the limitations of current MRI acquisitions. In the future, we hope to employ the presented techniques for real-time simulation of knee surgery.

Keywords

  • knee
  • ligament
  • real-time
  • simulation

References

Publication

Published version (Springer)
Preprint version (PDF)
Bibliographic reference (BibTeX)

Related article

3D Anatomical Human (INRIA project)

CCIA 2006 – Conference

CCIA 2006 – Conference proceeding

|

Publication

Emili Hernàndez, Pere Ridao, Marc Carreras, David Ribas, Narcís Palomeras, Andres El-Fakdi, François Chung, Toni Almohaya, Xavier Ribas, Guillermo García de Marina, Joan Massich, Natàlia Hurtós; ICTINEU AUV, un robot per a competir; CCIA 2006: Congrés Català d'Intel.ligència Artificial, Associació Catalana d’Intel.ligència Artificial (ACIA), Perpignan, 2006.

Abstract

SAUC-E (Student Autonomous Underwater Challenge - Europe) és la primera competició en robòtica submarina per a estudiants que es dur a terme a Europa. Inspirada en les competicions americanes, per a competir en el SAUC-E, un grup d'estudiants han de dissenyar i construir un robot capaç de dur a terme una missió predefinida per l'organització, de forma totalment autònoma. Un grup d'estudiants i professors de la Universitat de Girona (UdG) hem decidit afrontar aquest repte construint el robot ICTINEU AUV. Aquest robot aprofitarà eines de maquinari i programari desenvolupades els darrers anys en el nostre laboratori. Aquest article presenta el robot que estem desenvolupant i presenta resultats preliminars (simulació en temps real) de la seva arquitectura de control, mostrant la viabilitat de la proposta.

Keyword

  • robòtica

References

Publication

Preprint version (PDF)
Bibliographic reference (BibTeX)

Related articles

SAUC-E competition (UdG project)
UdG 2006 (technical report)

Learn more

SAUC-E – Student Autonomous Underwater Challenge – Europe
ACIA – Associació Catalana d’Intel·ligència Artificial

SAUC-E competition

SAUC-E competition

|

UdG project @Girona, Spain (2006). Inspired by the American competitions, SAUC-E (Student Autonomous Underwater Challenge - Europe) is the first underwater robotics competition for students to be held in Europe. To be eligible, a group of students must design and build a robot capable of carrying out, autonomously, a mission predefined by the organization in the underwater environment.

The objective of this competition is to challenge the next generation of engineers to design and build an Autonomous Underwater Vehicle (AUV), and then to perform realistic missions in the underwater environment. The event is designed to encourage young engineers and scientists to think about underwater technology and its future possibilities, as well as to foster interest in innovation and technology, and to encourage careers in this field.

Eight teams are involved in the competition:

  • Heriot-Watt University (UK);
  • International University Bremen (DE);
  • UdG - Universitat de Girona (ES);
  • University of Bath (UK);
  • University of Glasgow (UK);
  • University of Leicester (UK);
  • University of Southampton (UK).

The VICOROB-UdG team is a multidisciplinary team of students and professors from the Computer Vision and Robotics Group (ViCOROB) of the Universitat de Girona (UdG). Its main objective is to participate in the SAUC-E 2006 competition by building the ICTINEU AUV robot. This robot leverages hardware and software tools developed over the last years in the group's laboratories (e.g. real-time simulation and control architecture). In August 2006, the VICOROB-UdG team won the SAUC-E 2006 competition held in London (UK).

Within the VICOROB-UdG team, my work consists in developing a program for the real-time tracking of underwater objects. This program, which involves the use of image processing algorithms, aims at ensuring the robot's ability to complete two specific tasks during the mission. The first task consists in navigating towards a mid-water buoy and impacting it, the second consists in navigating towards a cross laying on the pool bottom and throwing a marker towards the center of the cross.

References

Related articles

CCIA 2006 (conference proceeding)
UdG 2006 (technical report)

Learn more

SAUC-E – Student Autonomous Underwater Challenge – Europe
VICOROB-UdG team
ViCOROB – Visió per Computador i Robòtica
UdG – Universitat de Girona

UdG 2006 - Technical report

UdG 2006 – Technical report

|

Publication

David Ribas, Narcís Palomeras, Xavier Ribas, Guillermo García de Marina, Emili Hernàndez, François Chung, Natàlia Hurtós, Joan Massich, Toni Almohaya, Josep Vila; ICTINEU AUV takes the challenge; Universitat de Girona (UdG), Girona, 2006.

Abstract

Within 1857-1868, Narcis Monturiol developed the first Spanish submarine. Almost one hundred and fifty years later, a pioneer team of students of the University of Girona (UdG) decided to design and develop an Autonomous Underwater Vehicle (AUV) to face the Student Autonomous Underwater Challenge – Europe (SAUC-E). Our robot, called ICTINEU AUV, is the result of a multidisciplinary project involving undergraduate, graduate and Ph.D. students of industrial engineering and computer science. The prototype has evolved from the initial Computer Aided Design (CAD) model to become an operative Autonomous Underwater Vehicle (AUV) in the short period of seven months. The open frame and modular design principles, together with the compatibility with other robots previously developed at the lab, have been the main design philosophy. Hence, at the robot core, two networked computers give access to a wide set of sensors and actuators. The Gentoo/Linux distribution, with a 2.6 pre-emptive kernel, has been chosen as the onboard operating system. The real-time POSIX, together with the ACE/TAO CORBA-RT ORB, have been extensively used to develop the control architecture as a set of distributed objects with soft real time capabilities. Common software engineering practises have been applied to ensure software reliability including Unified Modelling Language (UML) design, extensive documentation using DoxyGen and the use of a Code Version Server (CVS) to handle the sharing of multiple code versions. Finally, in order to reduce the development time, concurrent engineering techniques based on Hardware In the Loop (HIL) simulation have been applied to overlap the hardware and software design and development.

References

Publication

Published version (PDF)
Bibliographic reference (BibTeX)

Related articles

SAUC-E competition (UdG project)
CCIA 2006 (conference proceeding)

Learn more

SAUC-E – Student Autonomous Underwater Challenge – Europe
UdG – Universitat de Girona

M.Sc. Thesis 2005 - Master's thesis

M.Sc. Thesis 2005 – Master’s thesis

|

Publication

François Chung, Jonathan Lousse; Supervision centralisée d'infrastructures distantes en réseaux avec gestion des alarmes et notification des alertes; Master’s thesis (M.Sc. Thesis), Institut Supérieur Industriel de Bruxelles (ISIB), 2005.

Abstract

Pour assurer la disponibilité permanente de leur infrastructure informatique, les entreprises ont rapidement compris que la supervision était devenue une ressource-clé. Bon nombre de logiciels de supervision existent mais, parmi tout ceux-là, Nagios est très certainement le logiciel Open Source le plus répandu et également le plus suivi par la communauté de développeurs.

La supervision a trois objectifs principaux: prévenir les incidents sur le réseau par extrapolation des données fournies, agir rapidement dès qu'un système est noté en erreur et permettre l'analyse "post mortem" d'un problème grâce aux informations collectées.

Bien que Nagios soit reconnu comme difficile à installer et à configurer, il possède un nombre impressionnant de fonctionnalités telles que la surveillance de services réseau (SMTP, POP3, HTTP, NNTP, PING, ...), la surveillance de ressources machine (charge du processeur, utilisation du disque, ...) et la conception simple des "plugins" qui permet à des utilisateurs de développer facilement leur propre service de vérification.

Dans le cadre de ce travail de fin d'études (TFE), nous avons mis en place une supervision centralisée de l'infrastructure informatique de EASI, une gestion d'alarmes en cas de problèmes sur le réseau et une notification des alertes par email. Pour effectuer cela, nous avons non seulement utilisé les plugins standards de Nagios mais nous avons également développé nos propres plugins.

De plus, nous avons créé un mode multi-utilisateurs avec une authentification via l'annuaire LDAP (Lightweight Directory Access Protocol) de EASI et nous avons sécurisé les échanges d'informations entre les serveurs Nagios par un système de clés publiques et privées. L'objectif à terme est d'étendre cette architecture à l'ensemble des clients de EASI.

References

Publication

Published version (PDF)
Presentation (PDF)
Bibliographic reference (BibTeX)

Related article

Centralized supervision (ISIB project)

Learn more

Nagios
EASI
ISIB – Institut Supérieur Industriel de Bruxelles

Languages

Recent articles

Categories

News

Recent news & Popular news

Search