المحاضرة السادسة: إعداد جدول المشروع

Project Management Six Session

Egypt ScholarsPresented by

Mohamed Khalifa HassanJan 2014

© Mohamed Khalifa, 2014 All Rights Reserved 1


7. Scheduling

7.1 Scheduling techniques 7.3 Critical path method 7.3 Logical schedule alternatives


7. Scheduling


7.1 Scheduling techniques

Activity sequencing is a planning process that involve identifying and documenting interactivity dependencies among project activities for the purpose of creating the project schedule.

7.1.1 Activity sequencing



DependencyRelationships

Description Example

Finish-to-start (FS) The predecessor activity must finish before the successor activity can start.

The foundation for the house must be finished (Activity A) before the framing can start (Activity B)

Finish-to-Finish (FF) The predecessor activity must finished before the successor activity can finish.

Construction must be finished (Activity A) before the building inspection can be finished (Activity B)

Start-to-Start (SS) The predecessor activity must start before the successor activity can start. Can be expressed as, "Activity A Must start before Activity B can finish”

The building design must start (Activity A) before the electrical layout design can start (Activity B)

Start-to-Finish (SF) The predecessor activity must start before the successor activity can finish. Activity A must start before Activity B can finish

The electrical inspections must start(Activity A) before you can finish dry walling (Activity B)

Activity BSuccessor

Activity APredecessor



Dependency determination:Establishes dependencies among the activities, creating logical sequences.

Dependency Description ExampleMandatory Hard Logic ; Dictated Work .The dependency is

inherent to the work itself. Activity must be done in specific sequence

Books can’t be bound before they’re printed

Discretionary Soft logic ; Preferred logic ; Best practice ; preferential logic . Dependencies defined by the project management team at their discretion

The sponsor would like to see the book’s cover design as soon as possible, so the team may decide to have the cover artwork done before the inside illustrations.

External Dependencies contingent on input from outside the project activities

The books can’t be printed until the shipment of paper arrives

© Mohamed Khalifa, 2010 All Rights Reserved8

7.2 Critical path method

• You created a project network diagram and acquired activity duration estimates to help you develop your overall project schedule.

• Now you can establish the start and finish times for each of the activities in your project and determine the duration of the entire project.

• You need to identify the critical path.

• Standard Diagram Notations• ES : Early start . The earliest time an activity can start.• EF : Early finish. The earliest time an activity can finish. The EF

for the first activity is same as its duration. • LF Late finish. The latest time an activity can finish. The LF for

the last activity is the same as its EF time.• LS late start. The latest time an activity can start. The LS for

last activity = EF-DU. LS for any predecessor activity = LF-DU• DU Duration. The number of work periods required for

completion of an activity.

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Critical path:-The Critical path is the network path that has the longest total duration. Activities on the critical path cannot be delayed or the whole project will be delayed unless subsequent activities are shortened.

© Mohamed Khalifa, 2010 All Rights Reserved


• The Critical Path calculation:– Calculated by doing forward pass to calculate ES & EF for each activity and then backward pass to

calculate the LS and LF for each activity.

– The path with longest total duration and no scheduling flexibility is the critical path (ES=LS & EF=LF) & Float = 0

• Float :– Float is the amount of time an activity can be delayed from its ES without delaying the project finish

date . In arrow diagramming method networks, float is called slack.Total Float = Late Start (LS) – Early Start (ES) OR Late Finish (LF) – Early Finish (EF).

• Free Float :– The amount of time an activity can be delayed without delaying the ES of any activity that

immediately follows it is known as free float. Free float is not shared among activities– Free Float = ES of successor activity – (EF of the last activity + Lag).

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Free Float

Total Float (Float) (Slack)Total Float

(Float) (Slack) © Mohamed Khalifa, 2010 All Rights

Reserved


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Lag© Mohamed Khalifa, 2010 All Rights

Reserved


Workshop(20 Min)

12© Mohamed Khalifa, 2010 All Rights Reserved


7.3 Logical schedule alternative7.3.1 Develop Schedule

Schedule network analysis:– Produce the project schedule through a mix of analysis– Schedule network analysis is a technique used to calculate the theoretical early and late start

and finish dates for all project activities. This also generates float or slack.– Schedule network analysis may be achieved using one of four methods:

Critical Path Method (CPM) ; Critical Chain Method ;What-if Scenario and Resource Leveling

Critical path method (CPM)– Analysis that calculates early and late start and finish dates for all activities in the

project.Critical Chain Method:

– Alters the project schedule to accommodate limits on resources. Involves adding buffer activities to keep focus on activity durations.


7.3 Logical schedule alternative

Resource leveling:– Assist in making scheduling decisions when there are resource management concerns.

What-if scenario analysis :– Analysis that involves creating a scenario, (“What if X happened?”), and then

calculating various possible project durations. – Simulation involves calculating multiple project duration with different set of

activity assumptions (Mont Carlo Simulation)

Adjusting lead and lags:– Leads and lags may need to be adjusted to accommodate other scheduling elements.



Schedule Compression:-

– Schedule compression is the shortening of the project schedule without affecting the project scope.

– Compression may be achieved one of two ways: 1 – Fast tracking 2 - Crashing

1 - Fast Tracking :• Fast tracking is the process of compressing total project duration by

performing some activities concurrently that were originally scheduled sequentially.

• Some fast-tracking may entail looking very creatively at the network diagram to see some discretionary dependencies could be done completely independently.



2 - Crashing:• Crashing is a schedule compression method that analyzes cost and schedule

tradeoffs to determine how to obtain the greatest amount of schedule compression for the least incremental cost.

• Crashing typically involves allocating more resources to activities on the critical path in an effort to shorten their duration and thereby increases project costs.



Schedule Tool:– May include available commercial software or in-house, custom-built applications.– Now you need to assign actual start and finish dates to each activity,



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Schedule BaselineA Schedule baseline is a specific version of the project schedule developed from the schedule network analysis. It is accepted and approved by the project management team as the schedule baseline

Schedule DataSchedule data for the project schedule includes the schedule milestones, schedule activates , activity attributes, and documentation of all identified assumptions and constrains.Supporting details include :-- Resource requirements by time period - Alternative schedules, such as best-case or worst case , not resource-leveled or resource leveled- Scheduling of contingency reserves

© Mohamed Khalifa, 2010 All Rights Reserved


المحاضرة السادسة: إعداد جدول المشروع

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