predic object dm design dsgr model facad dm problem object cl dm collect end model facad associ end cl end end size problem object end end iter object asc model facad associ end list conn arrai list model facad connect asc connect end conn conn size problem object ae conn object ae conn end class merg model facad model facad type ae model facad model facad type ae problem end navig merg model facad navig ae model facad navig ae problem model facad lower ae model facad upper ae model facad lower ae model facad upper ae problem problem 