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Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
Maylor Chapter 4[Word 195KB]
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Maylor Chapter 4[Word 195KB]

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  • 1. Project Management Modelling the project system – detail models TIME PLANNING TOOLS AND TECHNIQUES By Hitoshi Kumagai Trang Vu Dieu Lecturer Peter Ruepert Arie van Schooten 10 November 2000 Saxion Hogeschool IJselland European Master Facility Management
  • 2. Project Management Tools and Techniques – Time Planning 1. Introduction This paper shows the tools and techniques of time planning of projects. In Maylor Chapter 4, talking about the tools and techniques of time planning, cost planning and resource allocation. With the limitation of this paper, we are focusing on time planning that should be the most communicable in those tools and be shared by each project member. However, the paper summarises the Maylor chapter 4 to clarify the role of this chapter in this book. Then, this paper introduces the graphical techniques of time planning; such as, bar chart and network diagram (A-o-A and A-o-N technique), for presenting the plan, and shows the characteristics of each technique. This paper, then, introduce PERT as a technique to treat with uncertainty of time duration, and discuss about what the uncertainty affects on project. Finally, this paper shows the status of those tools in facility management and gives the discussion theme of the importance of those techniques on this field. 2. Summary; Maylor chapter 4 As Rosenau, Jr wrote in his book, ‘Successful project management’; “Project have a three dimensional objectives, which is the simultaneous accomplishment of the performance specification, the time schedule and the cost budget”. In this statement he highlights the importance of the time as well as cost for a project. Before going through to this chapter let us consider the planning processes of a project. Scope planning (1) Activity sequence(4) Activity definition (3) Schedule development Scope definition (2) Activity duration estimating(6) Resource planning (5) Cost estimating (7) Cost budgeting (8) Project plan development (9) Fig 2-1 Planning process1 The objectives of this chapter is: - To provide a toolbox for the project planer containing techniques that will handle varying level of complexity in the areas of time and cost. - To make these plans amenable to optimisation (improvement and risk avoidance) - To undertake the first level of revision of the plan to allow an attempt to reconcile the objectives with the resources available. Project time management includes the processes required to ensure timely completion of the project. William R.Duncan in his book “ A guide to the project management body of knowledge” says, the project time planning process includes major processes2: - Activity definition- Identifying the specific activities that must be performed to produce the various projects deliverables or identifying constituent activities of the project. - Activity sequencing – Identifying and documenting interactivity dependencies or determining the logical sequence. - Activity duration Estimating- Estimating the number of work periods which will be needed to complete individual activities. 1 William R.Duncan Pg 70 2 1
  • 3. Project Management Tools and Techniques – Time Planning - Schedule Development- Analysing activity sequences, activity durations and resource requirements to create the project schedule. Allow the plan to be communicated to all parties involved with the project and analysis and Scheduling Control- controlling changes to the project schedule. The importance of the time planning by using tools and techniques or the plan for the schedule dimension orders activities so you can identify the logical relationship between them. It will be shown to other involved people in the project. A good time planning will increase the reliability of the project. In the other hand, project cost management includes the processes required to ensure that the project is completed within the approved budget. The importance of the cost planning is to avoid a situation where actual project cost overruns the estimate or fail to get the job because of overestimating cost during the proposal and negotiation phase. It also includes following processes3: - Resource planning – Determining what resources (people, equipment and materials) and what quantities of each should be used to perform project activities) - Cost estimating – Developing an approximation (estimate) of the cost of the resources needed to complete project activities. - Cost budgeting – Allocating the overall cost estimate to individual work items. - Cost Control – Controlling changes to the project budget. 3. The tools and techniques of time planning With the limitation of this paper, we would like to focus on tools and techniques of time planning that is used in demonstrating the time planning. Management is continually seeking new and better control techniques to cope with the complexities, masses of data, and tight deadlines that are characteristic of many industries and their highly competitive environments today, as well as seeking better method for presenting technical and cost data to customers. Activity scheduling is properly the single most important tool for determining how company resources should be integrated so that synergy is produced. Activity schedules are invaluable for projecting time-phased resource utilization requirements as well as providing a basis for visually tracking performance. Most programs begin with the development of schedules so that accurate cost estimates can be made. The schedules serve as master plan from which both the customer and management have an end-up to date picture of operations. There are some techniques that are used in the demonstrating the time planning. The simplest form is a horizontal bar chart, then is A-o-A and A-o-N method. Certain guidelines should be followed in the preparation of schedules, regardless of the projected use or complexity: - All major events and dates must be clearly identified. If a statement of work is supplied by the customer, those dates shown on the accompanying schedule must be included. If for any reason the customers should be notified immediately. - The exact sequences of work should be defined through a network in which interrelationships between events can be identified. - All the schedules must identify the time constraints and if possible, should identify those resources requires foe each event. Although these guidelines relate to schedule preparation, they do not define how complex the schedule should be. Before preparing schedules, three questions should be considered: How many events or activities should each network have? How much of a detail technical breakdown should be included? Who is the audience for this schedule? 3 William R.Duncan Pg 73 2
  • 4. Project Management Tools and Techniques – Time Planning 3-1. Bar charts One industrial engineer popularised them during the World War 1, are frequently used for scheduling. This is the simplest technique in showing the time planning in a project. Bar chart is most commonly used for exhibiting program progress or defining specific work required to accomplish an objective. Bar chart often includes such items as listing of activities, activity duration, schedule dates, and progress- to- date. This example shows some activities required starting up a master plant. Each bar in the figure represents a single activity MASTER PLANNING FORM Material Study Project Month Activity 1 2 3 4 5 6 A-Select B-Obtain C-Build D-Debug E-Conduct Experiment F-Document Design G-Literature Review H-Theoretical Study J-Theoretical Report K-Final Report Fig 3-1 Example4of bar chart 3-2. Network diagram and Critical Path Analysis (CPA): There are many forms of network diagrams. Network diagram is any of several displays that link project activities (or task) and event with one another to portray the interdependencies with the predecessor, successor and parallel activities or events. There are some principle types including: activity on arrow (A- O-A), Activity on node (A-0- N). a) A-0-A Diagram: This is a method of constructing a project network diagram using arrow to represent the activities and concerning them at nodes to show the dependencies This method use only finish-to-start dependencies and may requires the use of dummy activities to define all the logical relationships correctly. B- Obtain Start (Activity) Finish (Arrow). A-Select Material Material <6weeks> D- Debug E- Experiment Events: <3weeks> <11weeks> <2weeks> C- Build F- Document K- Final Report <12weeks> <6weeks> <1weeks> Event preceding Activity Event following Activity H- Theoritical J- Report (Start Event) (Finish Event) G- Study Literature study Theory <6weeks> <10weeks> <5weeks> Fig 3-2 Convention A-o-A Fig 3-3 Example5 of A-o-A 4 Rosenaau, Jr. P84 5 Rosenaau, Jr. P87 3
  • 5. Project Management Tools and Techniques – Time Planning b) Analysing the network – critical path analysis (CPA): There are two new terms to be introduced to the diagram in Malor book: Earliest event time(ETT) : Determine by the activities preceding the event and the earliest time at which any subsequent activities can start. Latest event time(LET) : the same or latter than the EET and is the latest time at which all the previous activities need to have been completed to prevent the whole net work being held up. Having completed of network diagram, identifying the critical path that sequence of activities which begin and end in events where the EET=LET The critical path is that the sequences of activities which have no float or slack(Fig B- Obtain EET 3 Material 12 3-4). If the activities is not belonging to the 10 0 20 6 <6weeks> 40 12 Event 0 A-Select critical path it means that activity can start Label LET D- Debug Material late and can takes longer than expected. For <3weeks> <2weeks> more detail in critical path, read more about 0 12 C- Build Pert method. CPA is very applicable in the 10 0 <12weeks> 30 12 Critical Path network diagram. Fig 3-4 Critical path c) A-o-N diagram: It is similar to A-o-A but instead of presenting activities on arrow, it presents activities on node. There is the exception that dummies are not required for clarification or maintaining logic flow. A-Select B- Obtain Material Material <3weeks> <6weeks> E- Experiment <11weeks> Finish to start Finish to finish C- Build D- Debug <12weeks> <2weeks> K- Final Report <1weeks> F- Document <6weeks> G- Study H- Theoretical J- Report Star to start Start to finish Literature study Theory <6weeks> <10weeks> <5weeks> Fig 3-5. Convention A-o-N Fig 3-5. Example6 of A-o-N 3-3. Advantage and disadvantages for each method Bar charts are advantageous in that they are simple to understand and easy to change, easy to draw, good for static environments. It is also useful for providing overview of project activities, very widely used, and the basic of graphical interface for most PC software. However, they are difficult to up date where they are many changes, so that bar chart can quickly become obsolete and therefore discredited. It does not equate time with cost, nor help in optimising resource allocation. It also does not show the interdependencies of the activities, so it has little predictive value. Bar chart cannot show the result of either an early or late start in activities, so it does not show the status of the project. In addition, it does not show the uncertainty involved in performing the activity and therefore does not really admit itself to sensitivity analysis (See 4. PERT). Some limitation of bar chart can over come by using network diagram, by using this technique ( A-o-A, A- o-N) with critical part as effective tool for show the schedule to people. However network diagram are much more complicated than Bar chart and for that reason it is difficult to make people involved in the 6 Rosenaau, Jr. P87 4
  • 6. Project Management Tools and Techniques – Time Planning project understand. But also it does not make sure that all calculations in the network diagram is running in the right way, because all the elements can change during the implementation of the project. 4. Dealing with uncertainty, time estimation “PERT” Maylor introduces PERT (Programme evaluation and review technique), as a technique that deals with uncertainty in time estimation of project management. This technique is often confused with CPA which is explained above7. PERT requires three estimation; which are optimistic time, most probable time and pessimistic time, for an activity in creating network diagram. In other words, CPA is a special case of PERT, where those three estimation are same each other’s. Maylor shows two points. One is that the considerable activities (critical path) might be different between when its duration is uncertain and when certain. The other is that there is a way to evaluate probability of a project using this technique 4-1. Critical path in uncertain activities PERT allows dealing with uncertainly by estimating three times for each activity. - optimistic time (o) : how long the activity would take if the conditions were ideal; - most probable time (m) : time if condition were ‘normal; - pessimistic time (p) : how long the activity would take if a significant proportion of the things that could go wrong, did wrong. Then, calculating follow by above times - expected time (e) : [o + 4m +p]/6 (on the normal distribution bases. According to Lock, there are some authorities skewing distribution, because estimates are more optimistic rather than pessimistic. Therefore, following formula is also used; [o + 3m + 2p]) This expected times (e) are used for analysing critical path instead of only one estimated time for each activity. There are opportunities that the critical path is different between using expected time (e) and using most probable time (m) as only one estimation for each activity. For example, when estimating former way (fig 5-1), the critical path is A-C-F-H. On the other hand, the critical path is ADGH when using only one time estimation (fig 5-2). B 8 E 30 3 10 6 0 A 5 C 9 F 16 H 24 10 20 40 60 70 0 5 5 4 9 7 16 8 24 9 Critical Path B 30 E D 10 G 2,3,10 10 5,6,7 50 5 11 5 e=4 e=6 Fig 5-1. 0 A 5 C 9 F 17 H 25 10 20 40 60 70 0 3,5,7 5 3,4,5 10 5,7,9 17 6,8,10 25 e=4 e=7 e=8 D 11 G Critical Path 50 4,5,12 11 4,5,12 e=6 e=6 Fig 5-2. 4-2. Evaluating probability of a project PERT provides a way to evaluate probability of following statement. “Will the project finish within expected duration. The way is based on statistical basis using the standard deviation. The details of this evaluation are showed in the book pp94-97. It shows the smaller uncertainty of each activity, the bigger probability to complete in certain durations. For example, even only the pessimistic times (p) are different between fig 5-3 and fig 5-4, the probability increase from 0.2981 to 0.666. 7 Lock, p159 5
  • 7. Project Management Tools and Techniques – Time Planning 5 D 9 G 17 5 D 9 G 17 20 40 60 20 40 60 5 4,5,12 10 17 5 4,5,8 10 4,5,8 17 4,5,12 e=6 e=6 e=5.3 e=5.3 Probability of completion in 11days = 0.2981 Probability of completion in 11days = 0.6664 Fig 5-3. Fig 5-4. 4-3. PERT in practice Both Maylor and Lock write that PERT is commonly introduced as a technique for time estimation in many books. However, both two author say CPA, simply estimating one duration for each activity, is used more often, and sometime network diagrams are mistakenly referred as PERT for CPA8. Maylor also says many project manager nowadays do not use PERT because of their doubts for its accuracy. The idea of PERT seems to be better to use understanding the effect of uncertainty for on project management. 5. Time Planning in facility management How are those tools of time planning explained above used in facility management? At least in Japan, only ‘bar charts’ are often used in daily projects, not network diagrams. Network diagrams and CPA are used in rather big construction projects. We asked some facility managers who are leading in this field such as a facility manager of HPJ or IBM-J. They only know about bar chart, and often use it. Is ‘bar chart’ technique enough for facility management? We would like to give our class this question to discuss. 6. Conclusion This paper has shoed the tools and techniques of time planning; such as, bar chart is simple to understand and easy to draw for static environment, network diagrams can describe more complicated project and easy to handle critical path. Network diagrams also show the dependencies of each activity. PERT shows the idea of dealing with uncertainty. However, it is obvious there is no only one best way to show the time planning. The most important thing of these tools is how a project manager makes time planning communicable for the people who are involved in the project. Tools and techniques should be selected for the case, complexity and people involved. 8 Lock, D. p160 6
  • 8. Project Management Tools and Techniques – Time Planning REFERENCES Duncan, William R. Director of standards ‘A Guide to the Project management body of Knowledge’ Lock, D. ‘Project Management’ 6th Edition, 1996, Gower, London Maylor, H. ‘Project managemen’t 2nd Edition, 1999, Financial Times Pitman Publishing, London Rosenau, Jr. Millton D. ‘Successful project management’ 2nd Edition, 1992, Van Norstrand Reinhold, New York. Harold Kerzner, PH.D 5th Edition, “A systems approach to planning scheduling and controlling.” Ohio 7

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