Chapter 14, Problem 10PA

A

Summary Introduction

Interpretation: The order in which the jobs have arrived, the average flow time, tardiness and lateness are to be calculated and compared.

Concept Introduction:The process of planning the ordering of the activities involves based on the elements such as, priority, set up time and such other is referred to as sequencing.

Answer to Problem 10PA

After necessary calculations, it can be seen that the average flow time is 25, lateness is 9.5, and tardiness is 11.25.

Explanation of Solution

Under the given order rule:

Job	Processing Time	Flow Time	Due Date	Lateness	Tardiness
1	7	7	21	-14	0
2	3	10	7	3	3
3	5	15	8	7	7
4	2	17	5	12	12
5	6	23	17	6	6
6	9	32	16	16	16
7	14	46	38	8	8
8	4	50	12	38	38
	Average	25.00		9.50	11.25

Average Flow Time will be;

  $=\frac{7+10+15+17+23+32+46+50}{8}=\frac{200}{8}=25.00$

The average lateness will be;

  $=\frac{-14+3+7+12+6+16+8+38}{8}=\frac{76}{8}=9.50$

The average tardiness will be;

  $=\frac{0+3+7+12+6+16+8+38}{8}=\frac{90}{8}=11.25$

B

Summary Introduction

Interpretation: the shortest processing time is to be calculated.

Concept Introduction: The process of planning the ordering of the activities involves based on the elements such as, priority, set up time and such other is referred to as sequencing.

The process of scheduling involves assignment of the proposed jobs, equipment or people with the start and end times.

Explanation of Solution

Job

4

2

8

3

5

1

6

7

Job	Processing Time	Flow Time	Due Date	Lateness	Tardiness
4	2	2	5	-3	0
2	3	5	7	-2	0
8	4	9	12	-3	0
3	5	14	8	6	6
5	6	20	17	3	3
1	7	27	21	6	6
6	9	36	16	20	20
7	14	50	38	12	12
	Average	20.38		4.88	5.88

C

Summary Introduction

Interpretation: The earliest due date is to be derived.

Concept Introduction: The process of planning the ordering of the activities involves based on the elements such as, priority, set up time and such other is referred to as sequencing.

Explanation of Solution

Job

4

2

3

8

6

5

1

7

Job	Processing Time	Flow Time	Due Date	Lateness	Tardiness
4	2	2	5	-3	0
2	3	5	7	-2	0
3	5	10	8	2	2
8	4	14	12	2	2
6	9	23	16	7	7
5	6	29	17	12	12
1	7	36	21	15	15
7	14	50	38	12	12
	Average	21.13		5.63	6.25

Below is the required comparison of the derived solutions:

	Average Flow Time	Average Lateness	Average Tardiness
FCFS	25.00	9.50	11.25
SPT	20.38	4.88	5.88
EDD	21.13	5.63	6.25