[IGSTK-Developers] notes from tcon today and picture of new Polaris Vicra system

[Kevin Cleary]

Hi everyone:

 

We had a very nice and short tcon today about the state machine issues and
plans for the next few weeks. The participants were: Kevin Cleary, Patrick
Cheng, Kevin Gary, David Gobbi, Rick Avila, Luis Ibanez, and Andinet
Enquobahrie (OK I confess, I had to look at Andinet's name on the Kitware
web site);

 

Here are a few notes from today:

*	We went over the agenda for the Board Review meeting. Rick noted
that FDA issues should be added somewhere to the agenda.
*	Kevin Gary reviewed the state machine diagrams he had put on the
web. He noted that there were three examples on the page with base and
derived classes and they were using different mechanisms. 
*	There were some questions about the DICOMImageReader and the fact
that the ConnectImage call at the end of the method was not part of the
state machine. This led to a discussion of when a method should be managed
by the state machine and when not. Luis stated the key factors were: 1)
whenever you have to decide if you want to invoke the method or not and 2)
whenever the result of the method will decide whether other things are done
or not. Kevin Gary still thought the ConnectImage call should be managed by
the state machine and this issue was not settled.
*	We then discussed the dispatcher idea. Luis noted that the main
motivation for introducing the dispatcher was that the original state
machine has problems with re-entrancy. He also noted that the dispatcher was
not the only mechanism for doing this, but one option to look at and there
may be other ways to handle this problem.
*	David had sent an email earlier about some issues he saw with the
dispatcher and summarized the issues in the tcon. One of his major concerns
was that the dispatcher could lead to a lot of events and code re-writing.
*	We then discussed the mechanism of passing information between state
machines. Luis has suggested an event/observer mechanism as a means of
ensuring robustness. Luis stated that the Get() method may not be robust
because it can be used any time and is not tied into the state machine
model.
*	David suggested that it is fine at times to use Get() methods and
that the calling program can do its own checks in many cases. He felt that
the event/observer mechanism may complicate the code too much and may not be
worth it.
*	Kevin Gary noted that it may not be a good compromise to mix the
notion of a Get() method with that of an observer pattern. 
*	So that we can moved forward, it was decided to table the issues of
the Dispatcher and Event/Observer mechanism until the board meeting. It was
also decided that Rick Avila at Kitware would try to convene an internal
review group to discuss these issues.
*	We will also try to build two demos at Georgetown for the board
review: one using the new Polaris Vicra tracker (see picture - just came in
this morning!) and the other using the Aurora electromagnetic tracker. The
demos will be built by Patrick Cheng and James Zhang at Georgetown and will
use the Revision 6 / Release 2 version of the software. Luis can also make
an experimental branch in the sandbox to try out his dispatcher and other
ideas.
*	It was decided to move the Revision 6 code this week since all the
reviews are in. Luis and Andinet will move their code first and notify the
mailing list, followed by David Gobbi (his code plus Heesu's code) and then
Julien.
*	Everyone should make their travel plans now for the review meeting
as noted in the other email and on the Wiki at
http://public.kitware.com/IGSTKWIKI/index.php/One_Year_Project_Review_Board_
Meeting_and_ITK_Course_at_Georgetown
*	Finally, we will have a tcon this Thursday at 3 pm EST and noon
California time (for those of us at MICCAI). The new teleconferences numbers
are on the Wiki.

 

I will try to paste this on the Wiki as well. Thanks for your participation
today.

 

Kevin

  

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Kevin Cleary, Ph.D.                        Work phone: 202-687-8253
Associate Professor                        Work fax: 202-784-3479
Deputy Director  
                            
Imaging Science and Information Systems (ISIS) Center
Department of Radiology                    Pager: 202-901-2033
Georgetown University Medical Center       Cell phone: 202-294-3409
2115 Wisconsin Avenue, Suite 603           Home phone: 301-299-0788
Washington, DC, 20007                      Home fax: 301-299-0789

 

ISIS center:  <http://www.isis.georgetown.edu/> www.isis.georgetown.edu
Research group:  <http://www.caimr.georgetown.edu/> www.caimr.georgetown.edu
WashCAS:  <http://www.washcas.org/> www.washcas.org
Email:  <mailto:cleary at georgetown.edu> cleary at georgetown.edu
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