Reminder: Guenter Tusch Talk at 2:30 in Ry276

[Margery Ishmael]

Department of Computer Science/The University of Chicago

Ryerson Hall -- 1100 E. 58th Street

COLLOQUIUM ANNOUNCEMENT


Friday, 10 November at 2:30 pm in Ryerson (Annex) 276
(To be followed by refreshments in Ryerson 255)

Guenter Tusch
Title: 'Optimal sequential decisions based on a POMDP model - application 
to liver transplantation'.

Abstract: Sequential decision making is investigated in different fields as 
robotics, economics, or medicine. The present investigation aims at the 
construction of a sequential decision procedure derived from a partially 
observable Markov decision process (POMDP) model. An optimal clinical 
management strategy based on a risk assessment of patients is to be found. 
A decision theoretic cost model different from the general approach has 
been selected for this clinical management (and classification) task: costs 
were determined by specifying a minimum acceptable sensitivity and 
specificity of the overall procedure. The aim is to construct a decision 
procedure to determine if a patient is a high risk patient or not and to 
estimate the probabilities that are necessary for the model from clinical 
data. This is achieved by finding the earliest possible decision epoch 
where a final decision can be made under these quality restrictions. 
Solution method is non-linear optimization combined with
a robust partial classification method. The probabilities necessary for the 
model are estimated from data of a clinical study in liver transplantation 
patients. Decision epochs were at donor organ assessment, immediately 
before surgery and post operatively in the intensive care unit. Parameters 
obtained within decision epochs were combined to scores by artificial 
neural networks (ANNs). The encouraging results show the applicability of 
the model in the clinical setting.

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end abstract

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Margery Ishmael
Department of Computer Science
1100 E. 58th St.
Chicago, IL 60637

tel: 773 834-8977  fax: 773 702-8487

marge at cs.uchicago.edu 
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