Precedence diagram method - Wikipedia
The general information of these cases is summarized in Table 1. The rest of The precedence relationships between activities in Case 1 are shown in Fig. 1. in a Precedence Diagram. ©Sheila Belayutham LOGO. Labelling of Precedence Activity. Activity. Description. (Duration). ES. LS. EF. LF ❖In CPM, logical relationship shows that an activity must . For the above table, draw and activity on. A Precedence Diagramming Method (PDM), which is sometimes also known as the Activity Activity on Arrow (AOA) diagram emphasizes milestones (events), and the AON diagram emphasizes tasks. Finish To Finish (FF) Relationship .. do you start to draw a table of those Dependencies.. what is on which column .
Mandatory dependency is inherent in the nature of the work. Can you test it before the development finishes? Therefore, there is a mandatory dependency between the development of the screen and testing of the screen in this case.Use forward and backward pass to determine project duration and critical path
The second type of dependency in Precedence Diagramming Method is Discretionary Dependency which is known as preferred, preferential or soft logic as well. Discretionary dependency is determined by the project team and can be changed in order to shorten the project.
Activities remain same but the order changes.
Precedence Diagramming Method (Activity on Node Method) in Scheduling
This is an example of the discretionary dependency in Precedence Diagramming Method. The third type of dependency in Precedence Diagramming Method is External dependency.
External dependencies come from outside of the project. For instance, in order to start your project, there is another project that must be completed first, this is an example of external dependency.
Or, if there is a government regulation that must be completed to continue the rest of the project activities, this is an example of external dependency in Precedence Diagramming Method as well.
Network analysis - activity on arc
The fourth type of dependency in Precedence Diagramming Method is Internal dependency. Internal dependency in Precedence Diagramming Method involves a precedence relationship between project activities. Activities must be performed in order to complete the project. For instance, before the architecture team finishes the design of the building, construction work cannot start.
This is an example of internal dependency. For example, let us say that you coding a program for a client, and the client is providing you the characteristics of the program.
In this case, you cannot finish coding for your program until the client gives you his complete requirements.
Here, both activities should finish simultaneously. Start to Start SS Here, the second activity cannot be started until the first activity starts. Both activities should start simultaneously. Suppose you have to apply a primary coating on a wall.
To apply the coating, you also need to clean the wall. Therefore, one team will start cleaning the wall and second team will paint it.
- Precedence diagram method
The formal definition of the latest times is given by: Float Consider an activity running in the network diagram from node i to node j. Hence we can form the table below: The easiest way to remember how to do the float calculation in AOA networks is by: Latest time at the activity end node - Earliest time at the activity start node - Activity time Note in particular how whether an activity is critical or not CANNOT be reliably deduced from whether the earliest and latest times coincide at the start and end nodes unlike AON networks.
For example consider nodes 8 and 9 in the above network - they both have earliest and latest times that are identical, with two activities between them - yet only one of those activities is critical.
Network analysis example UG exam The table below defines the activities within a small project. Activity Start End Completion time node node weeks 1 1 2 2 2 1 3 4 3 2 4 7 4 3 4 3 5 3 5 7 6 4 5 3 7 5 6 4 8 4 6 6 9 6 7 2 10 4 7 7 In addition to the above information, activity five cannot start until three weeks after the end of activity one.
Draw the network diagram. Calculate the minimum overall project completion time. Calculate the float time for each activity and hence identify the critical path. Comment on the potential effect upon the overall project completion time and the critical path of: Cutting the completion time of activity eight by three weeks?
Increasing the completion time of activity four by two weeks? Cutting the completion time of activity seven by two weeks? Will the project finish on time if at the end of six weeks the status of the project is: Finished - activities one, two and four In progress - activity three five weeks to completion and activity five four weeks to completion Solution The network diagram is shown below.
How to Create a Precedence Diagram or a Project Network Diagram
Note the introduction of node 8 and the two dummy activities 11 and 12 to correctly represent the condition that activity five cannot start until 3 weeks after the end of activity one. We then have the following calculation of earliest start times to determine the minimum overall project completion time. To determine the float times and which activities are critical we need to work out the latest start times.