A distribution graph including the nodes involved in {TAIL ~ the distribution} spanned out by {HEAD ~ logical links} assigned cost values is constructed 
A distribution graph including the nodes involved in { TAIL ~ the distribution } spanned out by { HEAD ~ logical links } assigned cost values is constructed
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH