of the selected processing unit the process uses the processing unit as the descendant processing unit in the remainder of the process in 2004 the process estimates the processing time of the descendant processing unit in 2005 the process obtains processing time requirement for the descendant processing unit a gap between the estimated processing time and the requirement is called slack in 2006 if a slack exists the process proceeds to 2007 otherwise 2001 in 2007 the process moves a sub set of u201c the operator set and tuple set to move u201d to the descendant processing unit and update u201c the operator set and tuple set to move u201d in 2008 if u201c operator set and tuple set to move u201d unit is empty the process terminates otherwise the process returns to step 2001 when the process terminates it calculates the difference between the original operator and tuple assignment to processing units and the modified one and the difference is the output turning now to fig6 a an exemplary component diagram of a code estimation and loading unit is shown block 301 performs estimation of potential operators operator assignment to processing units is given by an allocator block 301 inspects and determines which processing unit will not be able to perform assigned operator application within the.