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UID:1900@i2m.univ-amu.fr
DTSTART;TZID=Europe/Paris:20170926T140000
DTEND;TZID=Europe/Paris:20170926T160000
DTSTAMP:20241209T145914Z
URL:https://www.i2m.univ-amu.fr/evenements/analyse-spectrale-de-la-complex
 ite-du-cortex-cerebral/
SUMMARY:Hamed Rabiei (I2M\, ALEA-SI\, LSIS-I&M\, INT-MeCA): Analyse spectra
 le de la complexité du cortex cérébral
DESCRIPTION:Hamed Rabiei: Title: Spectral analysis of the cerebral cortex c
 omplexity\n\nAbstract: Surface shape complexity is a morphological charact
 eristic of folded surfaces. In this thesis\, we aim at developing some spe
 ctral methods to quantify this feature of the human cerebral cortex recons
 tructed from structural MR images. First\, we suggest some properties that
  a standard measure of surface complexity should possess. Then\, we propos
 e two clear definitions of surface complexity based on surface bending pro
 perties. To quantify these definitions\, we extended the recently introduc
 ed graph windowed Fourier transform to mesh model of surfaces. Through som
 e experiments on synthetic surfaces\, we show that our curvature-based mea
 surements overcome the classic surface area-based ones which may not disti
 nguish deep folds from oscillating ones with equal area. The proposed meth
 od is applied to a database of 124 healthy adult subjects. We also define 
 the surface complexity by the Hölder regularity of fractional Brownian mo
 tions defined on manifolds. Then\, for the first time\, we develop a spect
 ral-regression algorithm to quantify the Hölder regularity of a given fra
 ctional Brownian surface by estimating its Hurst parameter H. The proposed
  method is evaluated on a set of simulated fractional Brownian spheres. Mo
 reover\, assuming the cerebral cortex is a fractional Brownian surface\, t
 he proposed algorithm is applied to estimate the Hurst parameters of a set
  of 14 fetal cerebral cortices.\n*Membres du jury :\nPierre Borgnat\, ENS 
 Lyon\, rapporteur\nUmberto Castellani\, University of Verona\, rapporteur\
 nBruno Torresanni\, I2M (AMU)\, examiner\nIsabelle Bloch\, Telecom ParisTe
 ch\, examiner\nRoberto Toro\, Institut Pasteur\, examiner\nJulien Lefèvre
 \, LSIS (AMU)\, supervisor\nOlivier Coulon\, LSIS (AMU)\, supervisor\nFré
 déric Richard\, I2M (AMU)\, supervisor\n\nLiens :\n- theses.fr\n- Soutena
 nce à l'INT (La Timone)\n-\n-
CATEGORIES:Soutenance de thèse,ALEA,Signal et Apprentissage
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TZID:Europe/Paris
X-LIC-LOCATION:Europe/Paris
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DTSTART:20170326T030000
TZOFFSETFROM:+0100
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