Project Scheduling (1) Tran Van Hoai Faculty of Computer Science & Engineering HCMC University of Technology Tran Van Hoai

What is project management? Project is not business as usual (operations) – Operations means repetitive, permanent, semi- permanent Tran Van Hoai2 Project management (PM) is the discipline of planning, organizing, securing and managing resources to bring about the successful completion of specific engineering project goals and objectives

Primary challenges of PM To achieve all of the predefined project goals To honor the preconceived project constraints – Typical constraints are scope, time, and budget Tran Van Hoai3

Brief history (1) 1900: PM has been practiced in civil engineering projects 1910: Gantt chart, proposed by Henry Gantt 1916: 5 management functions, proposed by Henri Fayol <1950s: PM performed by Gantt charts, and informal techniques and tools Tran Van Hoai4

Brief history (2) 1950: mathematical project scheduling models developed – Critical Path Method (CPM) – Program Evaluation and Review Technique (PERT) Technology developed – Certification – Standard – Organizations –…–… Tran Van Hoai5

Approaches (1) Traditional approach Tran Van Hoai6 Waterfall model in Software Development

Approaches (2) Critical Chain Project Management (CCPM) – More emphasis on resources – Based on Theory of Constraints (Goldratt [1984]) Guarantee that resources are ready when critical chain tasks must start Extreme Project Management (XPM) – PERT-based models do not work well for multi- project company environment – to manage very complex and very uncertain projects “lightweight” models, human interaction management Tran Van Hoai7

Approaches (3) Event chain methodology – Complement CPM and CCPM methodologies – identify and manage events and event chains to cope with uncertainty Tran Van Hoai8 PRINCE2 – Structured approach – Automatic control

Approaches (4) Process-based management – Maturity models: CMMI (Capability Maturity Model Integration) Tran Van Hoai9

Processes (stages) Initiation Planning or development Production or execution Monitoring and controlling Closing Tran Van Hoai10 In R&D projects (much explorative elements), these stages may be supplemented with decision points In R&D projects (much explorative elements), these stages may be supplemented with decision points

Initiation (1) To determine the nature and scope of the project – Must be performed well Tran Van Hoai11

Plan for initiation Analyzing the business needs/requirements in measurable goals Reviewing of the current operations Financial analysis of the costs and benefits including a budget Stakeholder analysis, including users, and support personnel for the project Project charter including costs, tasks, deliverables, and schedule Tran Van Hoai12

To plan time, cost and resources adequately to estimate the work needed and to effectively manage risk during project execution Planning & Designing Tran Van Hoai13 determining how to plan (e.g. by level of detail or rolling wave) developing the scope statement selecting the planning team identifying deliverables and creating the work breakdown structure identifying the activities needed to complete those deliverables and networking the activities in their logical sequence estimating the resource requirements for the activities estimating time and cost for activities developing the schedule developing the budget risk planning gaining formal approval to begin work determining how to plan (e.g. by level of detail or rolling wave) developing the scope statement selecting the planning team identifying deliverables and creating the work breakdown structure identifying the activities needed to complete those deliverables and networking the activities in their logical sequence estimating the resource requirements for the activities estimating time and cost for activities developing the schedule developing the budget risk planning gaining formal approval to begin work

Scheduling Tran Van Hoai14 Define work activities Sequence work activities Identify work activity resource Estimate work activity duration Schedule activities

Executing To complete the work defined in the project management plan to accomplish the project's requirements Tran Van Hoai15

Monitoring & Controlling To observe project execution so that potential problems can be identified in a timely manner and corrective action can be taken, when necessary, to control the execution of the project Tran Van Hoai16

Closing formal acceptance of the project to archive of the files and to document lessons learned Tran Van Hoai17

Project scheduling - definition Project = – Collection of tasks (activities) – A task requires other tasks accomplished before it starts (precedence relations) – Factors affecting completion time Resources Detail level of the project target Tran Van Hoai18

Objectives Determining a schedule leading to earliest completion time for entire project Calculate the likelihood a project completed within a certain time period Finding minimum cost to finish the project by a certain date Finding a schedule smoothing out resource allocation … Tran Van Hoai19

Klonepalm 2000 activity description ActivityDescription Manufacturing activities APrototype model design BPurchase of materials CManufacture of prototype model DRevision of design EInitial production run Training activities FStaff training GStaff input on prototype models HSales training Advertising activities IPreproduction advertising campaign JPost-redesign advertising campaign Tran Van Hoai20

Precedence relations ActivityImmediate predecessorsEstimated completion time (days) A-90 BA15 CB5 DG20 ED21 FA25 GC,F14 HD28 IA30 JD,I Tran Van Hoai21

PERT/CPM network Network representation reflecting precedence relations Network G = (V,A) – V: vertex set = set of activities, v i = estimated completion time – A: arc set = set of precedence relations a ij if activity j is preceded by activity i Tran Van Hoai22

Klonepalm 2000 PERT/CPM network Tran Van Hoai23 A 90 A 90 B 15 B 15 F 25 F 25 I 30 I 30 G 14 G 14 D 20 D 20 H 28 H 28 E 21 E 21 J 45 J 45 C5C5 C5C5

PERT/CPM approach PERT/CPM analyses are – To determine minimal possible completion time – To determine a range of start and finish times for each activity (such that project completed in minimal time) Earliest times (ES,EF) – Computed by forward pass Latest times (LS,LF) – Computed by backward pass Tran Van Hoai24

Earliest/Latest Start/Finish Times Tran Van Hoai25 ES(A) EF(A) LS(A) LF(A) EF(X) = ES(X) + Weight(X) LF(X) = LS(X) + Weight(X) ES(X) = MAX Y=immediate predecessor of X {EF(Y)} EF(X) = ES(X) + Weight(X) LF(X) = LS(X) + Weight(X) ES(X) = MAX Y=immediate predecessor of X {EF(Y)}

ES/EF Sequence Tran Van Hoai26 A 90 A 90 B 15 B 15 F 25 F 25 I 30 I 30 G 14 G 14 D 20 D 20 H 28 H 28 E 21 E 21 J 45 J 45 C5C5 C5C5 0,90 90,105 90,115 90, , , , , , ,194 (Minimal) Estimated completion time = 194

LS/LF Sequence Tran Van Hoai27 A 90 A 90 B 15 B 15 F 25 F 25 I 30 I 30 G 14 G 14 D 20 D 20 H 28 H 28 E 21 E 21 J 45 J 45 C5C5 C5C5 0,90 90,105 90,115 90, , , , , , , , , , , ,129 90, ,11595,110 0,90

Slack times To measure the amount of time an activity can be delayed from its ES without delaying the project’s estimated completion time Tran Van Hoai28 Slack(X) = LS(X) – ES(X) Critical path are those with slack time = 0 Slack(X) = LS(X) – ES(X) Critical path are those with slack time = 0

Critical path Tran Van Hoai29 A 90 A 90 B 15 B 15 F 25 F 25 I 30 I 30 G 14 G 14 D 20 D 20 H 28 H 28 E 21 E 21 J 45 J 45 C5C5 C5C5 0,90 90,105 90,115 90, , , , , , , , , , , ,129 90, ,11595,110 0,90 Critical path = longest path

Analyses of possible delays What if an activity on critical path is delayed ? What if an activity not on critical path is delayed ? What if multiple delays occur ? Tran Van Hoai30