1. Production Activities Those that can be taken directly from plans and specifications 2. Procurement Activities procurement of material and equipment 3. Management Decision Activities Activities that can be created by management to avoid certain situations  Delay Concrete  Company Vacation TYPES OF ACTIVITIES

ij Activity Event (a) Basic Activity Basic Logic Patterns for Arrow Diagrams

2 A (b) Independent Activities 410 B A 6 B 9 (c) Dependent Activities Basic Logic Patterns for Arrow Diagrams (cont.)

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

(f) A Cross C 1616 D 1414 A 1212 B Activities C and D both depend upon the completion of Activities A and B Basic Logic Patterns for Arrow Diagrams (cont.)

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

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

Removal of Redundant Dummies A A A A B B B B CC Original DiagramDiagram after removal of redundant dummies (a) (b)

Removal of Redundant Dummies (cont.) A A A A C C B C BB Original DiagramDiagram after removal of redundant dummies (c) (d) BE C E EE

Combining Beginning and Ending Nodes AC E BF

Combining Beginning and Ending Nodes (cont.) 2812 AE CF B (a) Incorrect Representation (b) Correct Representation

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 “compass” direction on the drawing have any significance. (An exception to this rule is discussed under “Time-scaled Networks”.)

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).

Initial Activity List -Remodeling Chemical Laboratory Activity list –Strip room –Repair floor –Lay vinyl floor –Rough-in plumbing and electrical –Finish plumbing and electrical –Replace existing fume duct –Install new fume hood –Install base cabinets –Instal wall cabinets –Install chemical sink –Paint cabinets –Paint walls and ceiling

Preliminary Activity List - Remodeling Chemical Laboratory Activity List –Strip room –repair walls and ceilings –Repair floor –lay vinyl floor –rough-in plumbing and electrical –finish plumbing and electrical –replace existing fume duct –install new fume hood –install base cabinets –instal wall cabinets –install chemical sink –paint cabinets –paint walls and ceiling –obtain vinyl floor covering –obtain cabinets –obtain fume hood –obtain chemical sink –painter availability

Activity List with Dependencies - Remodeling Chemical Laboratory No.Activity listDepends Upon 1Strip room— 2Repair walls and ceilings1,5,7 3Repair floor1,5 4Lay vinyl floor3,12,13,14 5Rough-in plumbing and electrical1 6Finish plumbing and electrical2,3,5,9,10,11,19 7Replace existing fume duct1 8Install new fume hood2,3,16 9Install base cabinets2,3,8,15 10Instal wall cabinets2,3,7,15 11Install chemical sink2,3,5,9,17 12Paint cabinets6,8,9,10,11,18 13Paint walls and ceiling2,3,6,8,9,10,18 14Obtain vinyl floor covering— 15Obtain cabinets — 16Obtain fume hood— 17Obtain chemical sink— 18Painter availability— 19Install 2/3 base cabinet2,3,9,15

Retailing wall arrow diagram - start event approach Footing 1 Wall 1 Footing 1 Wall 1 Wall 2 28 Footing 1 4 Wall 1 10 Wall 2 6 Wall 1 Wall 2 Footing 1 Footing 2 (b) (c) (d) (a)