Dear Richard,
 in recent years, I have devoted a lot of my research effort to the development 
of (theoretical basis for) the 
geometric methods, which can be used to find a global maximum of quality 
criterion (=score) over BN structures. 
This, in the end, seems to lead to the application of methods of (integer) 
linear programming, for which wonderful 
speedy software packages have been developed by specialists in mathematical 
optimization

Thus, I have mentioned that there were some papers devoted to the algorithms
for finding the global maximum and some computational experiments based on that 
have been made. 
These are mainly
- dynamic programming approach by Silander+Myllymakki 
- integer linear programming approach by Jaakkolla, Sontag, Globerson and Meila 
- integer linear programming approach by Cussens (2 papers)
- higly relevant is also the research by C.deCampos +Ji on "pruning"

Of course, my co-authors (in particular S.Lindner) also made some preliminary 
computational experiments.
You may find references to the above mentioned papers (and some description of 
our approach) in a couple of papers:

- M. Studený, J. Vomlel, R. Hemmecke ``A geometric view on learning Bayesian 
network structures''
International Journal of Approximate Reasoning 51 (2010), n.5, 578-586.
a preprint available through staff.utia.cas.cz/studeny/a28.html
[BTW: in this paper a very simple example is given showing that GES can fail to 
find the global maximum]

- R. Hemmecke, S. Lindner, M. Studený ``Characteristic imsets for learning 
Bayesian network structure'' 
   International Journal of Approximate Reasoning 53 (2012) 1336-1349.
a preprint available through staff.utia.cas.cz/studeny/a31.html
[Here you find most of the references]

I hope this helps. Regards from                                                 
 Milan Studeny

PS: in my view, the application of the integer linear programming approach in 
particularly promising
       research direction





Richard E. Neapolitan  napsal:
>                               Dear Colleagues,
>       This note concerns learning Bayesian networks from data,              
> an area in which I wrote a book in 2003. However, since then I have not kept 
> that close of a track of                          developments in the area. 
> The GES algorithm                          assumes the composition property,  
>                               and the                                    
> constraint-based PC algorithm and                                        more 
> advanced constraint-based algorithms                                          
> assume faithfulness or embedded                                            
> faithfulness.                                              So none of         
>                                        them would discover a                  
>                                         DAG in which                          
>                                 two variables                                 
>                          together have                                        
>                   an effect on a                                              
>             third variable,                                                   
>        but neither of                                                         
>  the variables                                                          has a 
> marginal                                                          effect. I 
> am                                                          wondering if      
>                                                     there are any heuristic   
>                                                        search                 
>                                          algorithms,                          
>                                 in a particular                               
>                            ones implemented                                   
>                        in available                                           
>                software, that                                                 
>          address this                                                         
>  situation.                                                          Clearly, 
> there                                                          are 
> modifcations                                                          of 
> these                                                          algorithms     
>                                                      that would do            
>                                               so.
>                                                           Thanks,
>                                                           Rich
>                                                                               
>                       -- Richard E. Neapolitan, Ph.D., ProfessorDivision of 
> Health and Biomedical InformaticsDepartment of Preventive 
> MedicineNorthwestern University Feinberg School of Medicine750 N. Lake Shore 
> Drive, 11th floorChicago IL 60611                  
-- 

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