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Transcript of 1 Lecture 3.5: Work Dependencies, Scheduling, IMP & IMS (SEF A16A) Dr. John MacCarthy UMBC CMSC 615...
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Lecture 3.5: Work Dependencies, Scheduling, IMP & IMS (SEF A16A)
Dr. John MacCarthyUMBC CMSC 615Fall, 2006
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Agenda Types of Schedules Event-Driven Schedules Events and Entry/Exit Criteria Resource Loaded Schedules Integrated Management Plan (IMP) Example PERT Chart “Time-Expressed” Schedules Integrated Management Schedule (IMS) Example Gantt Chart Scheduling Tools Summary
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Types of Schedules Event-Based Schedule:
Generally referred to as the Integrated Management Plan (IMP) Generally implemented as a Program Evaluation and Review Technique (PERT)
Chart Identifies key engineering management events and relates them to the WBS Identifies the key tasks and results expected to permit key events Identifies key dependencies between tasks and events Serves as basis for:
Schedule Control Resource (& Cost) Control & Prioritization Planning & Measuring Cost/Schedule Progress, i.e. Earned Value A valid time-based (detailed) schedule
“Time-Expressed” Schedule: Generally referred to as the Integrated Master Schedule (IMS) Generally implemented as a Gantt Chart Provides dates
For key events By which tasks are to be started and ended
Shows key temporal dependencies between tasks and events Resource loaded time-based schedules serve as basis for Earned Value
Measurement Generally derived from the Event-based Schedule (PERT Chart)
Note that my (and industry) usage of the term IMS is inconsistent with the SEF use of term
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Event-Driven Schedules DoDI 5000.2 indicates schedules
should be “EVENT-DRIVEN,” not “Time-Driven”:
Do not let a date on a schedule force an event,
The successful completion of event entry/ exit criteria should drive when an event occurs
The Integrated Management Schedule (IMS) is DoD “Event-Driven” Schedule (generally represented as a PERT Chart)
Process: Identify key events required to achieve
programmatic success Identify entry/exit criteria for those
events Identify tasks that must be performed to
satisfy entry/exit criteria Identify dependencies between tasks
and events Identify time to accomplish required
tasks (to satisfy entry/exit criteria) (Time) Schedule the events (and tasks)
accordingly
Key SE Events: SRR SFR PDR/SSR CDR/TRR SVR/FCA PCA
Key Events generally have documented Entry and Exit Criteria
Reality Check - All programs have real end dates associated with them. If the time-schedule derived from the event-schedule does not meet the required end date:
Entry/exit criteria may need adjustment
Task & task estimates may need adjustment
Customer may need to revise end-date
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Example Event Exit Criteria
Events have associated (Entry and) Exit Criteria Events should not occur until (Entry and) Exit Criteria can be met
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“Event-Based Schedule” Development
Identify what artifacts/ products (& associated tasks) need to be complete for each WBS element for each Event
Identify artifact/ product/ tasks dependencies
Provides basis for Earned Value
Graphic provides one example of how this can be done
Each program will have its own process and forms
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Example PERT Chart A PERT Chart is essentially a flow chart showing the dependencies
between events and activities (what activities need to be completed prior to what events and the complete/start dependencies between activities)
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Integrated Management Plan (IMP)
The IMP is. The IMP is generally used to develop a
schedule by fixing Customer dictated Event dates and determining the time required to complete required activities.
Generally the IMP takes the form of a (PERT) Chart
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Resource Loading of Schedules
Generally one identifies the following data for each task (to develop artifacts and support events):
Event(s) Supported WBS Reference (WBS Element and Work Package) Start Date End Date EV milestones and credit Task Dependencies (input/output) Resources required (generally staff months and skill type)
As such, the data exists to “resource load” the schedule As one transitions from an “event-based” schedule to a “time-based”
schedule, one can determine the (time-phased) staffing profile for the program, i.e., how many people (full time equivalents (FTEs)) are required (with what skills) as a function of time
Note: For a given amount of work, as the schedule is compressed, the number of FTEs required (for each skill set) will increase.
Note: Schedule compression and elongation each result in (different) inefficiencies that drive up the resource count
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“Time-Expressed” Schedules
In order to manage a program, one must eventually assign dates to Events and Tasks
The result is a “Time Expressed” or “Calendar-Based” Schedule
This is usually represented by a Gantt Chart
Time-Expressed Schedules are generated from the IMS
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Integrated Master Schedule (IMS)
Technically the IMS is a database that includes:
All Milestones/ Events All Activities/Tasks &
Activity/Task start/stop dates All Activity/Task & Event
dependencies WBS/Work Package References Often associated WBS/Work
Package information such as staff loading and cost
The IMS is almost never seen in its entirety, rather different “Views” of the IMS are provided depending on the purpose
The views are generally provides as “Gantt Charts”
Levels/Views of the IMS: Top-Level:
Major Milestones/Events, Activities, & Dependencies
Used by Top Management and the Customer Shown at Technical Reviews and PMRs
Total Detailed (the “Real”) IMS: All Milestones/Events, Activities, & Dependencies Provides basis for other views Rarely seen by anyone
IPT Mid-Level: Major Milestones/Events, Activities, &
Dependencies of interest to an IPT Used by IPT Manager Shared with IPT and Management
Work Package Detailed: All Milestones/Events, Activities, & Dependencies
associated with a given work package Developed & Used by Work Package Lead Shared with Mid-level management Serves as building block for Total Detailed (“Real”)
IMS
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Gantt Chart Example A Gantt Chart
represents: Events as “Taco Chips” Activities as “bars” Dependencies as
“arrows” Each Event and Activity
is labeled as a Row Events & Activities may
be Decomposed/Nested The date of an Event and
the duration each activity is indicated by its location in the Row
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Scheduling Tools Generally the IMP and IMS will be developed in a single tool that:
Permits one to develop a Event-Driven IMP “Schedule” (as a PERT Chart) Events & Activities Dependencies
Include WBS/Work Package References Enter planned and actual Resource Loading data Enter planned and actual cost data Enter planned and actual start/stop dates for events & activities Permits one to generate the Time-Expressed IMS & IMS Views (as Gantt
Charts) Permits one to generate planned and actual Resource Profiles Permits one to generate an Earned Value Report
Examples: MS Project
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Summary Schedules should be “Event-Based” Events should not occur until all Entry and Exit Criteria are
fulfilled The IMP is an Event-Based Schedule that is often represented
as a PERT Chart Events and activities in an IMP should be tied to the WBS Schedules need to be “Time-Expressed” The IMS is a database that includes Time-Expression The Gantt Chart provides a IMS may be viewed in a Time-
Expression Schedules are generally Resource Loaded Tools exist for the development of IMPs and IMSs that may
also be used to generate Earned Value Reports and Resource Profiles