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   Robust Inference in Dynamic Bayesian Networks:

   Application to Gene Expression Time-Series Data         

     Omer Berkman

    Time series gene expression experiments are very popular for studying a wide range of biological systems. We are interested in the problem of inferring a genetic regulatory network from a collection of temporal gene expression observations, in particular, with small number of observations. Few approaches were suggested for this hard problem and one of the most promising is the Dynamic Bayesian Network (DBN). Several studies have investigated the robustness of the DBN estimation, based on short time series of gene expression data, with the conclusion that robust estimation of a genetic regulatory network, under mild simplifying assumptions and without exploiting prior biologic knowledge, can be achieved provided that the number of temporal observations is in the hundreds. Unfortunately, this is unrealistic with current technologies, and raises the need of better learning methods.

     This project introduces a weak learner’s methodology for this inference problem, studies few methods to produce Weak Dynamic Bayesian Networks (WDBNs), and demonstrates their advantages regarding the DBN model on simulated and real gene expression data. Our results show that the novel algorithms produce more robust inference, with respect to the number of observations and the level of noise within the data. 

 

תיבת טקסט: Comparison between regular DBN inference (DBN1) and representative WDBNs' inference.  
Score (average of Sensitivity and Precision) is illustrated ersus the level of noise within the data. For each observed level of noise (5, 10, ... ,40) 20 random data sets, of 250 observations each, were sampled. Each of the data set contains 50 genes.

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