how to change node rank?

[hangkum chang]

i need to change the rank of a node after the dag has been formed. The purpose of changing the rank of a node is to perform attack like sink hole or wormhole. I think i have to modify the code in the objective function, more specifically the 'calculaterank' function. But i am stuck here. I have read some papers on sinkhole or wormhole attacks but couldnt get the code.CAn anyone please help me here?