Question

The following jobs are waiting to be processed at Rick? Solano's machine center.? Solano's machine center has a relatively long backlog and sets a fresh schedule every 2? weeks, which does not disturb earlier schedules. Below are the jobs to be scheduled? today, which is day 241 ?(day 241 is a work? day). Job names refer to names of clients and contract numbers. Compute all times based on initiating work on day 241.

(Job) (Date Job Received) (Due Date Duration (days))

BR-02 225 270 25

CX-01 230 320 35

DE-06 235 360 40

RG-05 231 310 30

SY-11 228 300 15

Using the EDD? (earliest due? date) decision rule for sequencing the? jobs, the order is? (to resolve a? tie, use the order in which the jobs were? received):

The average tardiness? (job lateness) for the sequence developed using the EDD rule? =

The percentage utilization for the sequence developed using the EDD rule? =

The average completion time for the sequence developed using the EDD rule? =

The average number of jobs in the system for the sequence developed using the EDD rule? =

Answer 1

The Earliest Due Date rule is used to minimize the maximum lateness of schedule. According to EDD rule, the jobs are sequenced from earliest to latest due date of job. The sequence of EDD is as follows:

1	2	3	4	5	6 = 5+4	7	8 = 7 - (240 day)	9 = Maximum (0, (6 – 8))
Sequence	Job	Date Received	Processing time	Work Begins	Flow Time	Job Due date	Starting from day 241	Job Lateness
								(Tardiness)
			pi			di
1	BR-02	225	25	0	0+25 = 25	270	270-240 = 30	=max(0, (25-30)) = max(0, -5) = 0
2	SY-11	228	15	25	40	300	60	0
3	RG-05	231	30	40	70	310	70	0
4	CX-01	230	35	70	105	320	80	25
5	DE-06	235	40	105	145	360	120	25
			145		385			50

Total Processing time = 145 days

Total flow time for 5 jobs = 385 days

Total tardiness = 50 days

Average tardiness = total tardiness/number of jobs in sequence = 50/5 = 10 days

Percentage Utilization = total processing time/total flow time x 100

Percentage Utilization = 145/385 x 100 = 37.66%

Average completion time = Total Flow time/number of jobs in sequence = 385/5 = 77 days

Average number of jobs in system = Sum of total flow time/Total processing time = 385/145 = 2.65

For EDD:

Average tardiness = 10 days

Percentage Utilization = 37.66%

Average completion time = 77 days

Average number of jobs in system = 2.65 jobs