Chapter 12 Network Scheduling Techniques Scheduling Techniques Gantt

Chapter 12 Network Scheduling Techniques

Scheduling Techniques • • Gantt or bar charts Milestone charts Line Balancing Networks – Program Evaluation and Review Technique (PERT) – Arrow Diagram Method (ADM) also called the Critical Path Method (CPM) – Graphical Evaluation and Review Technique (GERT) – Precedence Diagram Method (PDM)

Scheduling Advantages • Needed for planning • Evaluate alternatives (what-if’s) • Resource scheduling • Controlling

Bar (Gantt) Charts TASKS 1 2 3 4 5 MONTHS AFTER GO-AHEAD 1 2 3 4 5

Milestone Chart ACTIVITY TESTING ANALYSIS REPORT PRESENTATION TIME

Standard PERT Nomenclature 6 3 WEEKS COMPLETE TESTING 3 COMPLETE FINAL REPORT LEGEND EVENT ACTIVITY

Dependencies 26 31 31 18 18 7 7 BURST POINT 26 SINK

Simplified PERT Network 3 1 5 2 6 7 8 4 LEGEND: (TIME = WEEKS) EVENT ACTIVITY CRITICAL PATH ACTIVITY 9

Dummy Activities D A PRECEDING ACTIVITY DUMMY B C A B C D B A, B

NETWORK FOR HOUSE CONSTRUCTION 6 POUR BASEMENT FLOOR INSTALL DRAINS 1 EXC & POUR FOOTINGS 2 POUR FOUND. INSTALL ROUGH ELECT. & PLUMB 3 ERECT FRAME & ROOF 7 11 8 INSTALL COOLING & HEATING INSTALL DRY WALL 9 4 10 LAY FLOORING 12 INSTALL KITCHEN EQUIP. PAINT FINISH CARPETING LAY BRICKWORK INSTALL FIN. PLUMB 16 FINISH ELECTR. WORK 5 LAY STORM DRAINS FINISH ROOF 13 14 18 POUR WALKS & LANDSCAPE INSTALL ROOF DRAINAGE 15 FINISH FLOORS FINISH GRADING 17

Slack Identification ACTIVITY EARLIEST START TIME EARLIEST FINISH TIME C (8, 10) 2 (15, 17) TIME LATEST FINISH TIME LATEST START TIME

Schedule Compression • • Elimination of some parts of the project Addition of more resources Substitution of less time-consuming components or activities Parallelization of activities Shortening critical path activities Shortening early activities Shortening longest activities

Schedule Compression (Continued) • Shortening easiest activities • Shortening activities that are least • • costly to speed up Shortening activities for which you have more resources Increasing the number of work hours per day

Resource Leveling • Resource leveling is an attempt to eliminate the manpower peaks and valleys by smoothing out the period-toperiod resource requirements. The ideal situation is to do this without changing the end date. However, in reality, the end date moves out and additional costs are incurred.

Resource Allocation • Resource allocation (or resource limited planning) is an attempt to find the shortest possible critical path based upon the available or fixed resources. The problem with this approach is that the employees may not be qualified technically to perform work on more than one activity in a network.

Types Of Precedence Charts FINISH-TO-START ACTIVITY 1 START ACTIVITY 2 START-TO-START ACTIVITY 1 START ACTIVITY 2

Types Of Precedence Charts FINISH-TO-FINISH ACTIVITY 1 PERCENT COMPLETE FINISH ACTIVITY 2 ACTIVITY 1 50 % 20 % ACTIVITY 2