Basic Logic Patterns for Arrow Diagrams Event i

Basic Logic Patterns for Arrow Diagrams Event i Activity (a) Basic Activity Prof. Awad Hanna j

Basic Logic Patterns for Arrow Diagrams (cont. ) 2 A 4 B 10 (b) Independent Activities 3 A 6 B 9 (c) Dependent Activities Prof. Awad Hanna 12

Basic Logic Patterns for Arrow Diagrams (cont. ) 4 2 A C 6 B 8 Activity C depends upon the completion of both Activities A & B (d) A Merge 2 A B 4 C 6 8 Activities B and C both depend upon the completion of Activity A (e) A Burst Prof. Awad Hanna

Basic Logic Patterns for Arrow Diagrams (cont. ) 12 14 A B C 16 18 D 20 Activities C and D both depend upon the completion of Activities A and B (f) A Cross Prof. Awad Hanna

The use of dummy to maintain unique numbering of activities 2 4 2 A B C Divide node to correct 6 D (a) Incorrect Representation A 8 6 10 C 8 D 10 Dummy 4 B 5 (b) Correct Representation Prof. Awad Hanna

The use of dummy to maintain unique numbering of activities (cont. ) A Divide node to correct 4 10 B (a) Incorrect Representation A 4 10 B Dummy 11 (b) Correct Representation Prof. Awad Hanna

Removal of Redundant Dummies Original Diagram after removal of redundant dummies (a) A B (b) A B C C Prof. Awad Hanna

Removal of Redundant Dummies (cont. ) Original Diagram (c) (d) Diagram after removal of redundant dummies A C A C B E B E Prof. Awad Hanna

Combining Beginning and Ending Nodes A C E B F Prof. Awad Hanna

Combining Beginning and Ending Nodes (cont. ) 2 A B 4 6 8 E C 10 12 14 F 16 (a) Incorrect Representation 8 2 16 10 (b) Correct Representation Prof. Awad Hanna

Basic Rules of Network Logic Rule 1. Before an activity may begin, all activities preceding it must be completed. (Activities with no predecessors are self-actuating when the project begins. ) Rule 2. Arrows imply logical precedence only. Neither the length of the arrow nor its “x” direction on the drawing have any significance. (An exception to this rule is discussed under “Time-scaled Networks”. ) Prof. Awad Hanna

Basic Rules of Network Logic (cont. ) Rule 3. Event numbers must not be duplicated in a network. Rule 4. Any two events may be directly connected by more than one activity. Rule 5. Networks may have only one initial event (with no predecessor) and only one terminal event (with no successor). Rule 6. ^Even, odd, in fives or tens ^Smaller numbers to the left ^Each activity has its unique number Prof. Awad Hanna

Retailing wall arrow diagram start event (b) (a) approach Footing 1 Wall 2 Wall 1 (c) Wall 1 Footing 2 Footing 1 Wall 2 Wall 1 (d) 2 Footing 1 4 Footing 1 6 Prof. Awad Hanna Wall 1 8 Wall 2 10

Activity List with Redundant Removed Remodeling Chemical Laboratory Prof. Awad Hanna

Arrow Diagram Remodeling Chemical Laboratory Prof. Awad Hanna