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Critical Path Method (CPM) using Work Breakdown Structures (WBS)

This system provides a critical path method (CPM) task scheduling system having the following elements:

-Tasks are specified with combinations of spans, start dates, end dates, and interfaces to predecessor tasks. Spans can be set in days and part days. Dates can be set at the start of a day plus a decimal portion of a day.

-Task interfaces can specify a portion (percentage) of the predecessor and can include a delay in days. When a task A is made a predecessor of Task B, Task A automatically has a successor interface to Task B. Interfaces may be added, deleted, and edited as either a predecessor or successor.

-A "rubber" task may be defined by anchoring its endpoints by interfaces to two tasks or a date and a task.

-One or more tasks may be given a critical date. Critical dates will be computed for all predecessor tasks with the earliest date being applied where successor interfaces lead to more than one critical specification (or there is more than one path to the same critical date).

Progress (completed work) may be assigned to a task as a number of days  or as a percentage of the task (floating point).

- Tasks are placed in a Schedule Work Breakdown Structure (SWBS). SWBS is an hierarchical sequence. For example, consider the sequence: A, A1, A2, B, B1, B2, B3. For this example the two letter WBS tasks (A1, ... B3) are detailed tasks specified as discussed above with spans, dates, interfaces, etc. A and B are SWBS Summary tasks. Their properties are computed as a summary of those of subordinate tasks - first start, last end, best and worst case progress. Consider another example: M, M1, M1A, M1B, N, N1,N2,N2A, N2B. In that series M,M1,N, and N2 are SWBS Summary tasks. 

Cost Work Breakdown Structure (CWBS) vs. SWBS:

Often the acronym WBS refers to a project CWBS. CWBS differs from an SWBS primarily in purpose. The CWBS is a hierarchy of cost categories. By custom, a numbering scheme like 1., 1.1., 1.2., 1,2,1, 2.,... is used. Typically, the highest several levels are used to collect costs for specific items of hardware and supporting functional areas. If used for schedule purposes, these elements very often would each be represented by a Gantt line from program start to program termination. Thus, from a schedule point of view, a CWBS is of little or no value. With EASE PMS, a CWBS can be used for collecting costs. The user assigns elements of the SWBS to the CWBS. Labor and material requirements and expenditures are assigned to SWBS tasks and can be accumulated into the traditional Budgeted Cost for Work Scheduled (BCWS), Budgeted Cost for Work Performed (BCWP), and Actual Cost for Work Performed (ACWP) by CWBS categories and summary levels. If desired, they can also be accumulated against the SWBS.

Copyright 2015 William R. Conner

 

Actions with Arrow, Home, End, Page Up and Page Down Keys

Left / Right Arrows: Gantt charts - Moves the calendar area one sub element

                              Network - Moves the display one column

Up/Dn Arrows: Gantt charts - Moves the display one task

                        Network - Display one row - usually no action because display

                          is usually one window vertically

Pg Up/Dn:   Gantt charts - Moves display one page of tasks

Home:        Gantt charts - To top of the task list

                  Network - Left to first task

End:           Gantt charts - To bottom of task list

                 Network - Right to last window of tasks

Copyright 2015 William R. Conner

 

Installation and Set Up Instructions

Download easeinstall.exe from easepms.com.  You'll probably have to find it in your Download folder. (pmsdemo020607.exe and pmsdemo082809.exe are equivalent to easeinstall.exe if they come from easepms.com.  Zip files pmsdemo020607.zip and pmsdemo082809.zip contain easeinstall.exe.)  Files with other names (created by third parties) are not recommended.

Run easeinstall.exe (or one of the two equivalents named above).  You will have the choice of what folder to place the EASE software.  It will create a screen icon.  Double click on the icon and it will come up with a provided project - HouseA.pj1.  You can play around with it for a while at no risk.  Then, go to Help and open the Getting Started page to learn in a more orderly fashion.

Compute Schedule (F2) 

This computes the project. 

It may find data errors which prevent completion of the compute.  In that case, it will give you an error message like one of the following:

 

 

The problem here is that the task starting the project, A1A, has nothing to get it started.  Put in a start date and all is well.

 

 

 

 

 

 

The problem here is a task interface loop.  Note that A1B is a predecessor of A1C which then feeds A1E which then feeds A1B.  Remove the interface from A1E to A1B and the problem is solved.  Note the "* Suspect" flag.

Helpful Hints:  1) Choose the Detail Gantt display showing all tasks  and set Display Preferences to include Links.  A problem link is often very evident graphically - an unexpectedly long vertical bar or shorter links extending above (to earlier tasks) rather than below (to later tasks) a task bar.  Of course, reviewing changes made since the last clean compute is advised.  2) SaveAs to a temporary filename before making extensive changes searching for the problem so as to not confuse your project with those trial changes.  Then you can Save this temporary file without jeopardizing your actual project.  Under some circumstances, the interface listing may start showing unrelated interfaces generated by a previous set of interfaces.  Saving the (temporary copy of) the project will reset parameters and eliminate that distraction.

Help: Web Based Help System  - This help system

Splash Screen Copyright Notice - It shows when the software is launched  and can be be brought up again from Menu Help|Splash Screen Copyright Notice

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