[Forum SIS] Seminario Roberto Rocci, Università G. d'Annunzio di Chieti-Pescara

[dibattis a unich.it]

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  AVVISO DI SEMINARIO
   
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  Giovedì 15 giugno alle ore 15:00, presso l'aula dottorandi  
dell'Università G. d'Annunzio, Viale Pindaro, 42, Pescara
  si terrà il seminario:

  FINITE MIXTURES FOR SIMULTANEOUS CLUSTERING AND REDUCTION OF MATRIX  
VALUED OBSERVATIONS

  Prof. Roberto ROCCI
  Dipartimento di Economia e Finanza
  Università degli Studi di Roma Tor Vergata

  Abstract:

  Finite mixture models are often used to classify two-way (units by  
variables) data.
  However, two issues arise: model complexity and recovering the true  
clustering structure.
  Indeed, a huge number of variables and/or occasions implies a large  
number of model parameters, while the existence of noise dimensions  
could mask the true cluster structure.
  The approach adopted in the present work is to reduce the number of  
model parameters by identifying a sub-space containing the information  
needed to classify the observations
   nesting a PCA-like reparameterization into the classification model.
  This also helps in identifying and discarding noise dimensions that  
could coincide with some observed variables.
  The aforementioned problems become more serious in the case of  
three-way (units by variables by occasions) data where the  
observations are matrices rather than vectors.
  Our approach is extended to this case by nesting a three-way  
PCA-like reparameterization (named Tucker2) into the classification  
model.
  This allows us to reduce the number of parameters identifying noise  
dimensions for the variables and/or the occasions.
  The effectiveness of the proposals is assessed through a simulation  
study and an application to real data.


  Il seminario è organizzato dal Dipartimento di Scienze Filosofiche,  
Pedagogiche ed Economico-Quantitative, Università G. d'Annunzio di  
Chieti-Pescara.
  I colleghi interessati sono cordialmente invitati a partecipare.

  Tonio Di Battista