Scheduling Flashcards
SCHEDULLING
Process of planning and organizing tasks, resources, and activities to optimize efficiency and productivity. It ensures that jobs are completed in the right order, at the right time, and using the right resources.
Processing Time (ππ)
Definition: The actual time required to complete a job without interruptions.
Given Directly: This value is provided for each job.
Processing Time is NOT cumulative; it is the time needed to complete an individual job.
Each job has its own processing time, independent of other jobs.
Example: If Job A takes 5 minutes and Job B takes 3 minutes, the processing time of each job remains 5 and 3 minutes separately.
Weight (ππ)
The importance or priority of a customerβs loan. Higher weight means higher priority.
Weighted Shortest Processing Time (WSPT) Rule
The customers should be processed in increasing order of ππ/ππ
β
This means that customers with smaller values of ππ/ππ are scheduled first.
Formula for Ordering Customers (WSPT Rule):
The order is determined by computing ππ/ππ (Processing Time divided by Weight) for each customer.
The lower this ratio, the earlier the customer should be processed.
Flow Time
Cumulative and depends on completion time.
If all jobs arrive at the same time, Flow Time is equal to Completion Time.
Formula:
Flow Time = Completion Time - Arrival Time
(If all jobs arrive at time 0, then Flow Time = Completion Time)
Total Flow Time = Sum of all individual flow times.
Example: If an order arrives at time zero and is completed at 14 minutes, then the Flow Time is 14 minutes.
Total Flow Time
Total Flow Time is the sum of all individual flow times.
It is found by adding the flow times of all jobs together.
Example: If four jobs have flow times of 8, 10, 14, and 20 minutes, then the Total Flow Time is 8 plus 10 plus 14 plus 20, which equals 52 minutes.
Average Flow Time
Average Flow Time is found by dividing the Total Flow Time by the number of jobs.
Example: If the Total Flow Time is 52 minutes and there are 4 jobs, then the Average Flow Time is 52 divided by 4, which is 13 minutes.
Shortest Processing Time (SPT) Rule
The SPT rule schedules jobs in order of shortest processing time first.
It is used to minimize the total flow time.
Example: If job A takes 6 minutes, job B takes 2 minutes, and job C takes 4 minutes, the best order to process them is B β C β A.
Earliest Due Date (EDD) Rule
The EDD rule schedules jobs in order of their deadlines, with the earliest due date first.
It is used to minimize lateness.
Example: If job A is due in 4 hours, job B in 2 hours, and job C in 3 hours, the best order is B β C β A.
Tardiness
Tardiness is the amount of time a job is late beyond its due date.
It is found by subtracting the due date from the completion time.
If the job is completed before its due date, the tardiness is zero.
Example: If a jobβs due date is 10 minutes and it is completed at 12 minutes, its Tardiness is 2 minutes.
FINISH TIME
First homewrok
Finish Time = Days to Finish
Next Hw
Previous Hw Finish Time + Days to finish of the current Hw
It is cummulative
