Large Scale Systems Design G52LSS

Transcription

1 Large Scale Systems esign 52LSS Lecture 6 Project Scheduling With PRT Project Scheduling PRT iagrams onstructing Pert iagrams Learning outcomes: describe the purpose and steps of project scheduling within the SL; understand the purpose of Pert diagrams; appreciate the differences between on and o Pert diagrams; understand the information given by Pert diagrams; draw on and o Pert diagrams given the precedence table. School of omputer Science Large Scale Systems esign r ario Landa-Silva 1

2 Project Scheduling Project scheduling is part of project management within the Planning phase of the Systems evelopment Life ycle. Project. Set of (concurrent/consecutive) activities or tasks with clear beginning and ending points aimed to achieve a specific goal. The amount of available resources (time, personnel and budget) to carry out the activities is usually limited. Project Scheduling. llocate resources to execute all activities in the project. School of omputer Science Large Scale Systems esign r ario Landa-Silva 2

3 Objectives of Project Scheduling stablish beginning, ending and duration of each activity or task in the project alculate overall completion time of the project given the amount of usually limited resources etermine the critical path and its duration etermine the slack time for all non-critical activities and the whole project uide the allocation of resources other than time such as staff and budget Produce a tool (schedule) to aid the control phase of project management School of omputer Science Large Scale Systems esign r ario Landa-Silva 3

4 Steps of Project Scheduling efine activities or tasks according to the project objectives and at various levels of detail Identify precedence relationships or dependencies stimate time required to complete each task raw the (o or on) PRT diagram inserting dummy activities if required pply PM to calculate earliest and latest starting times, earliest and latest completion times, slack times, critical path, etc. onstruct a NTT chart If necessary, re-allocate resources and re-schedule ontinuously monitor/revise the time estimates along the project duration School of omputer Science Large Scale Systems esign r ario Landa-Silva 4

5 PRT iagrams Pert diagrams (also called network diagrams) reflects dependence relationships between tasks in a project. ctivity-on-node (on) diagrams Maybe more than one single start and end node Nodes represent activities rrows indicate precedence ctivity-on-arrow (o) diagrams One single start and one single end node rrows represent activities Nodes indicate beginning/end of activities School of omputer Science Large Scale Systems esign r ario Landa-Silva 5

6 xample 6.1 of Pert diagrams on Pert iagram, o Pert iagram School of omputer Science Large Scale Systems esign r ario Landa-Silva 6

7 xample 6.2 of Pert diagrams on Pert iagram, o Pert iagram School of omputer Science Large Scale Systems esign r ario Landa-Silva 7

8 onstructing PRT iagrams In o Pert diagrams, each activity must be uniquely identifiable by its start and end nodes. This means that the diagram must meet the following conditions: Two activities must not share the same start and end nodes No activity can have more than one start node or more than one end node. That is, there must be only one arrow for each activity Sometimes it is necessary to insert dummy activities (duration zero) in o Pert diagrams in order to maintain the clarity of the diagram and/or the correct precedence between tasks. School of omputer Science Large Scale Systems esign r ario Landa-Silva 8

9 xample 6.3 In this o diagram, two tasks are sharing the same start and end nodes., The solution is to insert a dummy task dummy task School of omputer Science Large Scale Systems esign r ario Landa-Silva 9

10 xample 6.4 In this Pert diagram, the difficulty is to insert activity., School of omputer Science Large Scale Systems esign r ario Landa-Silva 10

11 xample 6.4 (cont.) Inserting task as shown in any of the cases below is incorrect. School of omputer Science Large Scale Systems esign r ario Landa-Silva 11

12 xample 6.4 (cont.) The solution is to insert a dummy task so that the precedence of task is preserved., dummy School of omputer Science Large Scale Systems esign r ario Landa-Silva 12

13 xercise 6.1 onstruct the on and o Pert diagrams for the following precedence table. on, o School of omputer Science Large Scale Systems esign r ario Landa-Silva 13

14 xercise 6.2 onstruct the on and o Pert diagrams for the following precedence table. on H I,, H I, H o H I School of omputer Science Large Scale Systems esign r ario Landa-Silva 14

15 xercise 6.3 onstruct the on and o Pert diagrams for the following precedence table., on o School of omputer Science Large Scale Systems esign r ario Landa-Silva 15

16 xercise 6.4 onstruct the o Pert diagram for the following precedence table. H I,, H I School of omputer Science Large Scale Systems esign r ario Landa-Silva 16

17 xercise 6.5 onstruct the on and o Pert diagrams for the following precedence table. L I K H I,,, H J J K H I,J L School of omputer Science Large Scale Systems esign r ario Landa-Silva 17

18 dditional Reading hapter 3 of (ennis et al., 2006) hapter 3 of (Kendall and Kendall, 2005) hapter 5 of (Maylor, 2003) School of omputer Science Large Scale Systems esign r ario Landa-Silva 18