Scheduling Flashcards
Are effort and time measured in the same units?
No,
Effort = person-days or person-months
Time = days or months
Converting between person-days to days equation
T = E / N
What do letters mean
T is time
E is effort
N is number of people
Does relationship of T= E/N E and T hold in general?
No, because some people can not work on task at same time (screwing in lightbulb)
Very small tasks can only be worked on by one person at a time
Relationship only applicable for N= 1
Larger values of N the benefit of additional people declines and ultimately become negative
If all tasks can be done at same time, how long will project take?
However long the longest task will take
If all tasks depend on each other, how long will project take?
Sum of the times required for each task
Tha amount of time required to complete a project depends on what two things?
Effort required for each task
Dependencies between tasks
Basic data needed to calculate time required to complete a project:
Duration = time required to complete each task Dependencies = which task must be completed before a specific task can be started
How should tasks be numbered?
Lower numbered tasks should not depend on higher numbered tasks to ensure no dependency cycles
A task that has no duration
dummy task
The tasks that determine the minimum amount of time required to complete the project
critical tasks
The amount of time that a task can slip without the project falling behind
Slack/Float
Critical tasks involve the calculation of…..
slack
Chart where tasks are represented as rectangles and dependencies re represented as arrows
Gantt Chart
How to find the critical task using Gantt Chart
Work backwards from the task with the latest finish time, Then, the predecessor that is part of the critical sequence is the predecessor that itself has the latest end time
How is slack represented in Gantt Charts
Straight horizontal lines
Planning method where the data from the task table and dependency table are used to construct a graph in which the vertices represent milestone and edges represent tasks.
Program Evaluation and Review Technique (PERT)
Events that can be used to mark the progress of the project
milestones
How was critical sequence of tasks determined in PERT
the longest path from the first event to the last event
Planning, contructs a time0cost curve for each task based on the normal time and the crash time for that task (to account for the relationship between effort and time/cost). Uses linear optimization problem to identify min cost way to complete project
Critical Path Method (CPM)
ID
Task identifier
D
Task Duration
ES
Earliest Start Time (ES)
EF
Earliest Finish time
LS
Latest start time
LF
Latest finish time
S
Slack
What are lines connecting boxes in CPM called?
Edges
The start time for task i assuming the preceding tasks are completed as early as possible
Earliest start time
The sum of the earliest start time and the duration
Earliest finish time
The last time the task can be completed without delaying the project beyond its earliest time
Latest finish time
The latest finish time minus the duration
Latest start time
When finding latest finish time, if 2 edges, pick the max or min latest start time?
Min
How to calculate slack time
The difference in latest finish time and earliest finish time
