As the second year of the PhD seminars comes to an end, we propose the following questionnaire so that the quality of the PhD seminars continues to improve. The questionnaire is anonymous. We greatly appreciate your participation and hope that you will write as much details as possible. After all, the PhD seminars are “par les doctorants, pour les doctorants”.
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Calendar
June 2017 Monday Tuesday Wednesday Thursday Friday Saturday Sunday May 29, 2017 2:00 pm: Digital Health, Biology and Earth: Part VI
2:00 pm: Digital Health, Biology and Earth: Part VIMay 29, 2017 –
Chairman
Selma Souihel - BIOVISION
Talk 1
Title:
Canard Mediated (De)Synchronization in Coupled Phantom BurstersSpeaker:
Elif Koksal - MathneuroAbstract:
Collective dynamics of coupled slow-fast oscillators have a great importance in the context of physiology when microscopic and macroscopic levels can be represented as relaxation oscillators. Synchronization of multiple timescale systems may involve synchrony of fast timescale dynamics, spikes, and/or slow timescale dynamics. In this presentation, we focus on the effect of canards on collective dynamics of an extended version of a neuroendocrine model which accounts for the alternating pulse and surge pattern of gonadotropin releasing hormone secretion. The model is formed by two FitzHugh-Nagumo oscillators that evolve on different timescales, with a feedforward coupling from the slow one (regulator) to the fast one (secretor). Global and local features of the resulting 4D three timescale model have been studied in the context of slow-fast dynamics and MMOs where folded singularities and associated canard trajectories have a particular importance. For instance, so-called secondary canards due to a folded node are responsible for the presence of a plateau with small oscillations in the model output, after the surge and before the pulsatility resumption. We extend the model to 6D by adding one more secretor and focus on the slow-fast transitions in the presence of coupling. We explore the influence of the relationship between canard structures and coupling on patterns of synchronization and desynchronization. We propose two different sources of desynchronization, induced by canards near a folded node and canards near a folded saddle, respectively.Talk 2
Title:
Longitudinal Parameter Estimation in 3D Electromechanical Models: Application to Cardiovascular Changes in DigestionSpeaker:
Roch Mollero - AscelpiosAbstract:
Computer models of the heart are of increasing interest for clinical applications due to their discriminative and predictive abilities. However the number of simulation parameters in these models can be high and expert knowledge is required to properly design studies involving these models, and analyse the results. In particular it is important to know how the parameters vary in various clinical or physiological settings. In this paper we build a data-driven model of cardiovascular parameter evolution during digestion, from a clinical study involving more than 80 patients. We first present a method for longitudinal parameter estimation in 3D cardiac models, which we apply to 21 patient-specific hearts geometries at two instants of the study, for 6 parameters (two fixed and four time-varying parameters). From these personalised hearts, we then extract and validate a law which links the changes of cardiac output and heart rate under constant arterial pressure to the evolution of these parameters, thus enabling the fast simulation of hearts during digestion for future patients.May 30, 2017 May 31, 2017 2:00 pm: PhD Seminars Special Edition
2:00 pm: PhD Seminars Special EditionMay 31, 2017 –
Chairwoman
Dimitra Politaki - NEO
Speaker:
Professor Nelly Litvak, University of TwenteTalk 1
Title:
Story-tellingWhen writing a paper or a grant proposal you will often hear `high-level’ advice such as: `write easier’, `make it crystal clear’, `explain what is new’, `make it exciting’. I will explain two hands-on specific techniques of story-telling, answering the question: HOW to write this way?
Talk 2
Title:
How to manage your adviser
A crucial point in establishing productive relationship with your advisors and getting the most out of your PhD time is to be proactive. Although this might not be obvious from the first sight, being proactive is the key to achieving your career goals. We will discuss what it means to be proactive, and what simple specific actions you can take to become proactive in managing your career.
June 1, 2017 June 2, 2017 June 3, 2017 June 4, 2017 June 5, 2017 June 6, 2017 June 7, 2017 June 8, 2017 June 9, 2017 June 10, 2017 June 11, 2017 June 12, 2017 2:00 pm: Digital Health, Biology and Earth: Part VII
2:00 pm: Digital Health, Biology and Earth: Part VIIJune 12, 2017 –
Chairman
Pascal Helson - TOSCA
Talk 1Title:
Optimal Transport Applied to Brain Computer InterfacesSpeaker:
Nathalie Gayraud - ATHENAAbstract:
Brain Computer Interfaces (BCI) allow their user to control a machine via acquisition of electroencephalographic signals (EEG), which are subsequently processed and transformed into commands. This transformation process can be described in three steps: at the beginning, the signal undergoes pre-processing, denoising and temporal division; Then, each signal fraction is transformed into a feature vector; Finally, these vectors are classified in a number of classes, which varies according to the BCI application. However, EEG signals have a low signal-to-noise ratio; To this is added the important cross session and cross suject variability. Therefore, calibration of the BCI, during which the user is required to perform a predefined task, must always precede its use. This allows the collection of labeled data, which is used in the training of the classifier of the current session. Nevertheless, this process can take several minutes, while being frustrating for the user. To date, various methods are used to improve the quality of acquired signals, while attempting to increase class separation. The optimal transport method is based on transport theory, where one seeks to find the optimal transport of some specified amount of mass from one domain to another. By applying this method, new, unlabeled data can be transported on the domain of the existing, labeled data and classified with the existing classifier.Talk 2
Title:
Dipole localization in Moon rocks from sparse magnetic data.Speaker:
Konstantinos Mavreas - APICSAbstract:
Moon has a really interesting magnetic behavior! Today it has no global magnetic field, nevertheless there are evidences showing that it used to have one in the past for billions of years. Paleomagnetic scientists try to understand the reasons of the creation and the evolution of this ancient magnetic field (which suddenly disappeared few million years ago), by studying the remanent magnetism of surface Moon rocks. In our study, we consider dipole recovery issues from sparse magnetic data, with the use of best quadratic
rational approximation techniques, together with geometrical and algebraic properties of the poles of the approximants.An open discussion on the PhD Seminars will follow the two talks.
June 13, 2017 June 14, 2017 June 15, 2017 June 16, 2017 June 17, 2017 June 18, 2017 June 19, 2017 June 20, 2017 June 21, 2017 June 22, 2017 June 23, 2017 June 24, 2017 June 25, 2017 June 26, 2017 June 27, 2017 June 28, 2017 June 29, 2017 June 30, 2017 July 1, 2017 July 2, 2017