predic object dm design dsgr model facad transit dm problem dm transit object sourc vertex model facad sourc dm model facad pseudost sourc vertex problem sourc transit pseudost model facad equal pseudost kind model facad kind sourc vertex model pseudost kind choic problem sourc transit choic object guard model facad guard dm guard guard model facad express guard model facad bodi model facad express guard model facad bodi model facad express guard length guard problem problem 