Scheduling Flashcards
What does scheduling include?
Sequencing
Personnel scheduling
operating room planning
project scheduling
Define scheduling
timing of usage of resources
often represented in Gantt charts
What is the scheduling hierarchy?
- Aggregate planning
- master production schedule
- material requirements planning
- shop floor schedule
Two types of sequencing
Flow shop
- all jobs processed on all machines in same order
- each job once on each machine
- example: assembly line
Job shop
- not all jobs require all machines
- sometimes same machine multiple times
- different jobs need machines in different order
Which performance measures exist?
Completion time
Tardiness
Flow time
Makespan
Define completion time
-exact time when final job finishes on final machine
Define tardiness
-Difference between due date and completion date
Define flow time
-Duration between release of a job and time of completion
Define makespan
- duration needed to complete all jobs
- from release of ´first job to completion of final job
which major goals does scheduling have?
Minimize flow times
- minimize max. flow time
- minimize average flow size for all jobs
Maximize punctuality
- only if every job had due date
- minimize total tardiness
- minimize nr. of tardy jobs
Which priority rules exist
First come first served (FCFS)
Shortest processing time (SPT)
Earliest due date (EDD)
What is project scheduling
- Precedence relations
- displayed as network
what is the critical path?
- path with no slack
- helps identify processes that are critical in regards to timing
define slack
time between differnt steps in project process
-should be minimized as it causes additional costs
