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Chapitre 6 Gestion de projets Project management.

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1 Chapitre 6 Gestion de projets Project management

2 - 2 - Plan Introduction The characteristics of projects The project manager Planning and scheduling projects The Gantt Chart PERT and CPM The Network Critical Path Method (CPM) PERT : probabilistic approach Project compression: trade-offs between time and cost Resource considerations

3 - 3 - Intoduction Health care managers may work on projects that are unique and nonroutine. Projects can be viewed as temporary endeavors undertaken to create new products and services. Examples: moving to a new location by a certain date, renovating an outpatient facility. Projects has considerable costs and involve a large number of activities that must be carefully planned and coordinate. Project management is an approach for handling these unique, one-time endeavors that have significant costs and significant effect on the organisation’s operation. Planning and coordination are essential to complete activities of the projects on time, within cost constraints, and with high quality result.

4 - 4 - Intoduction Most projects are expected to be complete with time, cost and performance guidelines. Goals must be established and priorities set. Tasks must be identified and time estimates made. Resource requirements have to be projected? Budgets have to be prepared. Once under way, progress must be monitored.

5 - 5 - The characteristics of projects Project life cycle: Formulation and analysis: recognise the need of the project, analyse the expected costs, benefits, and risks Planning: details of the projects, estimates of necessary human resources, time and cost. Implementation: project undertaken, time and resources consumed. Termination: reassign personnel and dealing with leftover and excess materials and equipment.

6 - 6 - The project manager Responsible for the organization and completion of the project Communicate among the project team and coordinate their activities Manage time and budget constraints Assess constantly the quality of the work done Set priorities among the tasks Ensure the activities being done in the necessary sequence Communicate with all relevant external players.

7 - 7 - Planning and scheduling projects Project management tools: Gantt chart Program Evaluation and Review Techniques (PERT) Critical Path Method (CPM) Activities are project steps that consume resources and/or time Crucial activities that requirement special attention to ensure on-time completion of the project can be identified, as well as how long others’ start can be delayed

8 - 8 - The Gantt Chart Useful scheduling project activities at the planning stage, and then monitoring them by comparing their actual progress to planned progress. Launching a new radiation oncology service ActivityTime A.Land acquisition4 wk B.Hire a radiation oncologist16wk C.Select contractor & develop a construction plan8 wk D.Build the facility24 wk E.Aquire equipment28 wk F.Hire technical staff4 wk G.Purchase & set up info syst. & software8 wk H.Testing of equipment4 wk Precedence relation ActivityPredecessor A.- B. - C. A, B D. C E. C F. D,E G. D, E H. F, G

9 - 9 - The Gantt Chart Time in weeks Activities A B C D E F G H Advantage: simplicity Disadvantages: cannot show the chronological relation among activities, cannot show how the delay of an activity impact the whole project

10 PERT and CPM n Tools for planning and coordinating large projects n Project managers can graph the project activities, estimate the project duration, identify the activities most critical to its on-time completion, and calculate how long any activity can be delayed without delaying the project. n PERT and CPM developed independently in late PERT by US government to speedup weapon development. CPM by Du Pont & Remington Rand Co. To plan and coordinate maintenance projects. n PERT considers the probabilistic nature and CPM mostly derterministic.

11 The Network n A network is a diagram of project activities and their precedence relationships. n An activity represented by an arrow is called activity on arc (AOA). n An activity can also be represented by a node and is called an activity on node (AON). n Most project management computer program are desgined using an AON network because of its simplicity. n A dummy arc with no time is needed to represent certain precedence relations in AOA. n Both are used in practice. Representation of one can be transformed into that of another.

12 The Network ActivityPredecessor A.- B. - C. A, B A BC Dummy activity A B C Activity on arc Nodes = beginning/end of activities = events Activity on node

13 Critical Path Method (CPM) n The netwok diagram shows the sequence in which activities must be performed. n On AON networks, it is common to add a start node preceding the first activities, and an end node to mark the completion. Radiation oncology service ActivityPredecessor A.- B. - C. A, B D. C E. C F. D,E G. D, E H. F, G Start A B C D E F G H End

14 Critical Path Method (CPM) n A path is a sequence of activities from the start node to the end node. n On AON networks, it is common to add a start node preceding the first activities, and an end node to mark the completion. Paths ACDFH ACDGH ACEFH ACEGH BCDFH BCDGH BCEFH BCEGH Start A B C D E F G H End

15 Critical Path Method (CPM) n The length of a path is the total time of activities on it. n The critical path is the path with the longest time. n It defines the expected project duration. n All activities on the critical path are critical activities. Path Lengths ACDFH = 44 ACDGH = 48 ACEFH = 48 ACEGH = 52 BCDFH = 56 BCDGH = 60 BCEFH = 60 BCEGH = 64 ActivityTime A.4 wk B.16wk C.8 wk D.24 wk E.28 wk F.4 wk G.8 wk H.4 wk

16 Critical Path Method (CPM) n CPM algorithm determines the following pieces of information: ES: the earliest time an activity can start LS: the latest time the activity can start and not delay the project EF: the earliest time the activity can finish LF: the latest time the activity can finish and not delay the project Activity name ES EF LS LF

17 Critical Path Method (CPM) Computing ES and EF times: n EF = ES + activity time (t) n The earliest start time (ES) of an activity is equal to the largest EF of its entering arrow (i.e. its predecessors). Activity name ES EF LS LF Start A B C D E F G H End Activity Time A.4 wk B.16wk C.8 wk D.24 wk E.28 wk F.4 wk G.8 wk H.4 wk

18 Critical Path Method (CPM) Activity name ES EF LS LF Start A B C D E F G H End Activity Time A.4 wk B.16wk C.8 wk D.24 wk E.28 wk F.4 wk G.8 wk H.4 wk

19 Critical Path Method (CPM) Computing LS and LF times: n LS = LF - activity time (t) n The latest finish time (LF) of an activity is equal to the smallest LS of its outgoing arrow (i.e. its successors). Activity name ES EF LS LF Start A B C D E F G H End Activity Time A.4 wk B.16wk C.8 wk D.24 wk E.28 wk F.4 wk G.8 wk H.4 wk

20 Critical Path Method (CPM) Activity name ES EF LS LF Start A B C D E F G H End Activity Time A.4 wk B.16wk C.8 wk D.24 wk E.28 wk F.4 wk G.8 wk H.4 wk

21 Critical Path Method (CPM) The allowable delay of an activity is called slack: n Slack = LS – ES or n Slack = LF - EF

22 Critical Path Method (CPM) Start A B C D E F G H End Start A B C D E F G H End Activity SlackCritical A.12No B.0Yes C.0Yes D.4No E.0Yes F.4No G.0Yes H.0Yes

23 Progrom Evaluation and Review Technique PERT : probabilistic approach When activity duration cannot be estimated with certainty, PERT uses three time estimates: n Optimistic time (o): length of time required under the best conditions n Pessimistic time (p): length of time required under the worst conditions n Most likely time (m): the most probable length of time required. Care should be taken to make the estimates as realistic as possible.

24 PERT : probabilistic approach These estimates can be used to find the average or expected time of each activity te, and the variance,  2. n Based on a beta distribution, which is similar to 3  estimation of Normal Law.

25 PERT : probabilistic approach n Under the assumption of independent activity times, the completion time of a path and its variance can be determined as follows: In PERT, completion time of a path is assumed to be Normally distributed completion times of different paths are assumed independent Simulation is now used for more realistic project evaluation & optimization.

26 PERT : probabilistic approach n Probability of a path finishes before a specified time ts: Where  (z) is the standard Normal distribution. n Probability of a projet of N paths finishes before a specified time ts: n In practice, only paths that are significant for the completion of the project are considered.

27 PERT : probabilistic approach Pathtpath  pathzPpath ACDFH ACDGH ACEFH ACEGH Significant paths BCDFH BCDGH BCEFH BCEGH Act. ompte   A B C D E F G H Project completed by 65, 66, 67, 70 weeks (proba = 0.32, 0.44, 0.55, 0.81)

28 PERT : probabilistic approach Réfléchir sur une méthode par simulation pour l’estimation de la probabilité de terminer un projet avant une date donnée.

29 Project compression: trade-offs between time and cost n Most activities can be speed up by more budget and more manpower. n In general, there is need of trade-off between direct compression cost and indirect overhead cost. Normal finish time Opt. compression Max compression Overhead & indirect costs Direct compression cost Total cost (TC)

30 Project compression: trade-offs between time and cost A general algorithm for project compression 1. Compute path lengths and identify the critical path 2. Rank the activities on the critical path according to their compression costs 3. Shorten the activity with the least compression cost and the critical path 4. Calculate the total costs 5. Compare the total cost of the current compressed time to that of the previous compression time; if the total cost has decreased, perform steps 1-4 again. Otherwise stop because the optimum compression time has been achieved.

31 Project compression: trade-offs between time and cost Example: The indirect costs for design and implementation of a new health info syst project are 8000€/day. Find the optimal project scheduling. Start A B C D E F G H End I ActivityNormal timeCompressed time Direct comp. Cost/day (in 000) A B75748 C42406 D E28267 F G40 0 H I Optimal cost = for 200 days.

32 Project compression: trade-offs between time and cost A linear programming approach

33 Resource considerations n Determining optimal schedules for complex project networks subject to resource limitations is an extremely difficult combinatorial problem. n A project may require a variety of different resources. n Heuristic methods are generally used to modify schedules obtained by more conventional means.

34 Resource considerations n In general, the inclusion of resource constraints has the following effects: n The total amount of scheduled slack is reduced n The critical path may be altered. Further, the zero-slack activities may not necessarily lie along one or more continuous paths n Earliest and latest start schedules may not be unique. They depend on the rules that are used to resolve resource limitations.

35 Resource considerations n Most heuristic methods involve ranking the activities according to some criterion and resolveing resource conflicts according to the sequence of the ranking. n Examples of ranking rules include: Minimum job slack (minimum) Latest finishing times Greatest resource demand (priority to bottleneck activities) Greatest resource utilization (select combination of activities that results in the maxi resource utilisation in any scheduling interval) n The first two methods tend to be the best performers. n Méthode sérielle à revoir.

36 Resource considerations n Example: Consider the project network below. Activity times, in days, are given in the figure. a) Determine ES, EF, LS, LF of all activities, draw the Gantt chart based on ES, but indicate the activity slack. How long is the project? b) A critical piece of equipment is required in order to complete the following activities (A, B, C, D, G, H). Determine a feasible schedule for the project assuming that non of these activities can be done simultaneously. c) Two resources, R1 and R2, are used for each activity. Assume that these are both consummable resources with daily requirements as follows (A, 4R1, 0R2), (B, 8, 6), (C, 10, 9), (D, 18, 4), (E, 12, 3), (F, 5, 12), (G, 3, 2), (H, 0, 6). Determine resource loading profiles based on the schedule found in part b). d) Based on the results of part c), determine the cumulative amounts of resources R1 and R2 consumed if the schedule found in part b) is used. ABCDEFGH AAA,BDCE,F Activity time pred

37 Resource loading profiles n A loading profile is a representation over time of the resources needed. n As long as the requirements associated with each activity are known, one can easily obtain the resulting loading profiles of all required resources. n Resources can be either consumable (cash, fuels) or nonconsummable (manpower). n A desirable feature of loading profiles is that they be as smooth as possible. n Large variations in resource requirements make planning difficult and may result in exceeding resource availability at some time. n The idea behind resource leveling is to reschedule noncritical slack in order to smooth out the resource usage, which is often possible by inspection.

38 Resource loading profiles Activities A B C D E F G H Res 1 Res 2

39 Resource considerations n Example: Consider the project network below. Activity times, in days, are given in the figure. a) Determine ES, EF, LS, LF of all activities, draw the Gantt chart based on ES, but indicate the activity slack. How long is the project? b) A critical piece of equipment is required in order to complete the following activities (A, B, C, D, G, H). Determine a feasible schedule for the project assuming that non of these activities can be done simultaneously. c) Two resources, R1 and R2, are used for each activity. Assume that these are both consummable resources with daily requirements as follows (A, 4R1, 0R2), (B, 8, 6), (C, 10, 9), (D, 18, 4), (E, 12, 3), (F, 5, 12), (G, 3, 2), (H, 0, 6). Determine resource loading profiles based on the schedule found in part b). d) Based on the results of part c), determine the cumulative amounts of resources R1 and R2 consumed if the schedule found in part b) is used. ABCDEFGH AAA,BDCE,F Activity time pred


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