BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Hilbert-Huang transform - A new method of analyzing unsteady\, non
 linear turbulent flow data - Julien Landel\, BPI &amp\; DAMTP
DTSTART:20090226T113000Z
DTEND:20090226T123000Z
UID:TALK16764@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:The Hilbert-Huang transform (HHT) is a new and powerful signal
 -processing technique developed in the late 1990's by Dr Norden E. Huang a
 nd his colleagues. The HHT can analyse any nonlinear and non-stationary si
 gnals without mathematical requirements. It has been applied successfully 
 for the past ten years in various domains: biomedical applications\, chemi
 stry and chemical engineering\, digital image analysis\, financial applica
 tions\, fluid mechanics\, meteorological and atmospheric applications\, oc
 ean engineering\, seismic studies\, structural applications\, health monit
 oring\, and system identification. It proceeds in two steps: first an inge
 nious method called the empirical mode decomposition (EMD) decomposes a di
 screte time-series into intrinsic mode functions (IMFs). These IMFs reveal
  the different mechanisms mingled in the original signal. Second\, the Hil
 bert transform is applied to each IMF to compute the instantaneous frequen
 cy and amplitude. It eventually yields a physically meaningful time-freque
 ncy-amplitude spectrum\, which gives very useful insights about the underl
 ying mechanisms of the phenomenon studied.\n\nThe basics of the HHT algori
 thm are introduced. Then\, key points\, such as the stopping criterion for
  the sifting process\, the end-effect\, and the problem of mode mixing\, a
 re described. Some solutions addressing these problems are then presented.
  Finally\, results obtained with two signals\, the length-of-day data (LOD
  data) and vortex-shedding data are discussed. The analysis of the LOD dat
 a\, initially studied by Dr Huang and colleagues.\, is a good example show
 ing the efficiency of the EMD. The results obtained with the second signal
  have revealed a nonlinear phenomenon of intra-wave frequency modulation.\
 n\n
LOCATION:Open Plan Area\, BP Institute\, Madingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR