Precedence diagram and identify the element

A task having 12 work elements and their logical relationship and time ( in Seconds ) taken is given in the table below.

Construct Precedence Diagram: Construct the precedence diagram where, i = element number, j = time in seconds

                                                                Figure: Precedence Diagram

Identify Element: In precedence diagram identify the element which do not have predecessors (does not follow other element) and enclose in a column and number that column as. Next identify the elements those immediately follow the element in column number 1 and enclose them in column number II. Similarly in column number III enclose all elements that follow the element in column number II. Continue this procedure until all elements are enclosed in columns. The element in the last column will not have any more elements to follow. By so constructing the columns the elements within a column can be assigned to works stations in any order, provided all the elements of the previous column have been assigned. At the same time we should not violate precedence order.