IV.   Conclusion.

PALM and Pre-PALM is a very efficient interface, allowing comunication between different programs and subroutines at the right time. This allows the devellopment of different sub-programs by many programmers, the interface between these codes being very easy to implement. It also allows module decomposition, thus letting the user change only one piece of code without changing the rest. It can also help the devellopers to have a better overview of their program structure.It makes data assimilation very simple to code and understand.

Data assimilation is also a very powerful tool, in areas where the simulation is done at the same time as observations are made (meteorology, missile guiding...) It alows to have better predictions of the behavior of a system without having very precise data about its initial state, but some complementary information about the evolution of the system.